Fix git-crrev-parse returning reverted commits instead of original commits

Also delete extraneous whitespace

BUG=685326

Change-Id: If7f68346fd27edf9a5dca315cfcfbca0decc2da6
Reviewed-on: https://chromium-review.googlesource.com/433158
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Dirk Pranke <dpranke@chromium.org>

git-crrev-parse

@@ -41,11 +41,10 @@ while [ -n "$1" ]; do
   remote_ref="${remote_ref/refs\/branch-heads/refs\/remotes\/branch-heads}"
   num="${commit_pos#*@\{\#}"
   num="${num%\}}"
-  
   if [ -z "$ref" -o -z "$num" ]; then
     git rev-parse "$1"
   else
-    grep_str="Cr-Commit-Position: $ref@{#$num}"
+    grep_str="^Cr-Commit-Position: $ref@{#$num}"
     git rev-list -n 1 --grep="$grep_str" "$remote_ref"
   fi