Remove obsolete codehaus snapshot repository

Since the gwt-maven plugin we are using is available in Maven
Central, we don't need to be looking at this snapshot repository
to locate the plugin.

Change-Id: Ie23d3e85231a08ae57f9ed9bcdda9274f2c3dbdd
Signed-off-by: Shawn O. Pearce <sop@google.com>
1 file changed