GM: add --missingExpectationsPath option, similar to --mismatchPath

gm/tests/run.sh

Index: gm/tests/run.sh
===================================================================
--- gm/tests/run.sh	(revision 9724)
+++ gm/tests/run.sh	(working copy)
@@ -108,12 +108,12 @@
   for IMAGEFILE in $(find $ACTUAL_OUTPUT_DIR -name *.png); do
     echo "[contents of $IMAGEFILE]" >$IMAGEFILE
   done
-  if [ -d $ACTUAL_OUTPUT_DIR/mismatchPath ]; then
-    for MISMATCHDIR in $(find $ACTUAL_OUTPUT_DIR/mismatchPath -mindepth 1 -type d); do
-      echo "Created additional file to make sure directory isn't empty, because self-test cannot handle empty directories." >$MISMATCHDIR/bogusfile
-    done
-  fi
 
+  # Add a file to any empty subdirectories.

[epoger, 2013/06/21 17:39:42]

Patchset 1 fixes the way we prevent empty subdirectories from being written.  No
changes to the GM binary yet, just the self-test.

+  for DIR in $(find $ACTUAL_OUTPUT_DIR -mindepth 1 -type d); do
+    echo "Created additional file to make sure directory isn't empty, because self-test cannot handle empty directories." >$DIR/bogusfile
+  done
+
   compare_directories $EXPECTED_OUTPUT_DIR $ACTUAL_OUTPUT_DIR
 }