Fix gclient "skip update on certain commands", again

Not all developers have =~ support in bash, apparently.
Switching to standard globbing.

R=tapted
TBR=maruel

Review URL: https://codereview.chromium.org/11369147

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@166867 0039d316-1c4b-4281-b951-d872f2087c98

gclient

@@ -5,7 +5,7 @@
 
 base_dir=$(dirname "$0")
 
-if ! [[ "#grep#fetch#cleanup#diff#" =~ "#$1#" ]]; then
+if [[ "#grep#fetch#cleanup#diff#" != *"#$1#"* ]]; then
   "$base_dir"/update_depot_tools
 fi