break; after handling --initial-client-data on command line

Not surprisingly,
"0x278,0x27c,0x280,0x274,0x288,0x978a70,0x978a80,0x978a90" is not a
valid directory to store metrics in.

Fortunately --metrics was processed before --initial-client-data in a
local build, otherwise this could have lurked for a long time. :(

R=mark@chromium.org
BUG=655788,656800

Change-Id: I3ac3d1b487f55ddf0172bac51f8d9efc411c3329
Reviewed-on: https://chromium-review.googlesource.com/406938
Reviewed-by: Mark Mentovai <mark@chromium.org>

handler/handler_main.cc

@@ -267,6 +267,7 @@ int HandlerMain(int argc, char* argv[]) {
               me, "failed to parse --initial-client-data");
           return EXIT_FAILURE;
         }
+        break;
       }
 #endif  // OS_MACOSX
       case kOptionMetrics: {