rebaseline_server: display as much info as possible if expected/actual image is missing

gm/rebaseline_server/testdata/outputs/expected/compare_configs_test.CompareConfigsTest.test_gm/gm.json

 {

[borenet, 2014/04/01 21:15:56]

I have no idea what these files mean, but I think I understand how they
changed...

   "extraColumnHeaders": {
     "builder": {
       "headerText": "builder", 
       "isFilterable": true, 
       "isSortable": true, 
       "valuesAndCounts": {
         "Test-Android-GalaxyNexus-SGX540-Arm7-Release": 7, 
         "Test-Mac10.7-MacMini4.1-GeForce320M-x86_64-Debug": 3
       }
     }, 
@@ skipping 25 matching lines @@
         "bigblurs": 2, 
         "bitmapsource": 1, 
         "displacement": 1, 
         "filterbitmap_checkerboard_192_192": 1, 
         "filterbitmap_checkerboard_32_2": 1, 
         "texdata": 1
       }
     }
   }, 
   "header": {
-    "dataHash": "-8308658702264135120", 
+    "dataHash": "7627783634950094306", 
     "isEditable": false, 
     "isExported": true, 
     "schemaVersion": 2, 
     "timeNextUpdateAvailable": null, 
     "timeUpdated": 12345678, 
     "type": "all"
   }, 
   "imagePairs": [
     {
       "extraColumns": {
         "builder": "Test-Android-GalaxyNexus-SGX540-Arm7-Release", 
         "config": "TODO", 
         "resultType": "no-comparison", 
         "test": "texdata"
       }, 
       "imageAUrl": null, 
       "imageBUrl": "bitmap-64bitMD5/texdata/3695033638604474475.png", 
-      "isDifferent": false
+      "isDifferent": true
     }, 
     {
       "extraColumns": {
         "builder": "Test-Android-GalaxyNexus-SGX540-Arm7-Release", 
         "config": "TODO", 
         "resultType": "no-comparison", 
         "test": "filterbitmap_checkerboard_32_2"
       }, 
       "imageAUrl": "bitmap-64bitMD5/filterbitmap_checkerboard_32_2/712827739969462165.png", 
       "imageBUrl": null, 
-      "isDifferent": false
+      "isDifferent": true
     }, 
     {
       "extraColumns": {
         "builder": "Test-Android-GalaxyNexus-SGX540-Arm7-Release", 
         "config": "TODO", 
         "resultType": "no-comparison", 
         "test": "filterbitmap_checkerboard_192_192"
       }, 
       "imageAUrl": "bitmap-64bitMD5/filterbitmap_checkerboard_192_192/3154864687054945306.png", 
       "imageBUrl": null, 
-      "isDifferent": false
+      "isDifferent": true
     }, 
     {
       "extraColumns": {
         "builder": "Test-Android-GalaxyNexus-SGX540-Arm7-Release", 
         "config": "TODO", 
         "resultType": "no-comparison", 
         "test": "bigblurs"
       }, 
       "imageAUrl": "bitmap-64bitMD5/bigblurs/17309852422285247848.png", 
       "imageBUrl": null, 
-      "isDifferent": false
+      "isDifferent": true
     }, 
     {
       "extraColumns": {
         "builder": "Test-Android-GalaxyNexus-SGX540-Arm7-Release", 
         "config": "TODO", 
         "resultType": "no-comparison", 
         "test": "bitmapsource"
       }, 
       "imageAUrl": "bitmap-64bitMD5/bitmapsource/16289727936158057543.png", 
       "imageBUrl": null, 
-      "isDifferent": false
+      "isDifferent": true
     }, 
     {
       "extraColumns": {
         "builder": "Test-Android-GalaxyNexus-SGX540-Arm7-Release", 
         "config": "TODO", 
         "resultType": "no-comparison", 
         "test": "3x3bitmaprect"
       }, 
       "imageAUrl": "bitmap-64bitMD5/3x3bitmaprect/2054956815327187963.png", 
       "imageBUrl": null, 
-      "isDifferent": false
+      "isDifferent": true
     }, 
     {
       "extraColumns": {
         "builder": "Test-Android-GalaxyNexus-SGX540-Arm7-Release", 
         "config": "TODO", 
         "resultType": "no-comparison", 
         "test": "aaclip"
       }, 
       "imageAUrl": "bitmap-64bitMD5/aaclip/14456211900777561488.png", 
       "imageBUrl": null, 
-      "isDifferent": false
+      "isDifferent": true
     }, 
     {
       "differenceData": {
         "maxDiffPerChannel": [
           136, 
           68, 
           34
         ], 
         "numDifferingPixels": 6081, 
         "percentDifferingPixels": 2.4324, 
@@ skipping 56 matching lines @@
     "imageB": {
       "baseUrl": "http://chromium-skia-gm.commondatastorage.googleapis.com/gm", 
       "description": "gpu"
     }, 
     "whiteDiffs": {
       "baseUrl": "/static/generated-images/whitediffs", 
       "description": "differing pixels in white"
     }
   }
 }