linux: switch to -Wno-format

Semantically it's the same as -Wformat=0, but Clang only accepts
this new one.  (A bug has been filed with Clang.)

Review URL: http://codereview.chromium.org/6489009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@74513 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/build/common.gypi b/build/common.gypi
index 4bc125cd..73a57d91 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -679,7 +679,7 @@
               '-Wno-deprecated',
               # Don't warn about printf format problems.
               # This is off by default in gcc but on in Ubuntu's gcc(!).
-              '-Wformat=0',
+              '-Wno-format',
             ],
           }],
           [ 'OS=="win"', {