Emit debug info on failed deletion of temp file.

LayoutTests/http/tests/local/fileapi/resources/temp-file-utils.js

 function createTempFile(fileName, fileData)
 {
     var xhr = new XMLHttpRequest();
     xhr.open("POST", "http://127.0.0.1:8000/resources/write-temp-file.php?filename=" + fileName + "&data=" + fileData, false);
     xhr.send();
     if (xhr.status != 200) {
         testFailed("Unexpected response status received: " + xhr.status);
         return;
     }
 
     var values = xhr.responseText.split('\n');
     if (xhr.responseText.indexOf("FAIL") == 0) {
         testFailed("Unexpected response text received: " + xhr.responseText);
         return;
     }
 
     return xhr.responseText;
 }
 
 function touchTempFile(fileName)
 {
     var xhr = new XMLHttpRequest();
     xhr.open("POST", "http://127.0.0.1:8000/resources/touch-temp-file.php?filename=" + fileName, false);
     xhr.send();
 }
 
 function removeTempFile(fileName)
 {
     var xhr = new XMLHttpRequest();
-    xhr.open("POST", "http://127.0.0.1:8000/resources/reset-temp-file.php?filename=" + fileName, false);
+    xhr.open("GET", "http://127.0.0.1:8000/resources/reset-temp-file.php?filename=" + fileName, false);
     xhr.send();
+    // Echo any errors that the script emits.
+    if (xhr.responseText > 0)
+        console.log("removeTempFile('" + fileName + "'): " + xhr.responseText);
 }