Fixes a bug in r2611: when doing a sloppy scan for JSNI 
references, @ signs that do not begin a valid JSNI
reference would cause an exception to be thrown.
This patch suppresses such errors and skips to the
next @ sign.

Review by: scottb



git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@2651 8db76d5a-ed1c-0410-87a9-c151d255dfc7