Mojo: Make mojob build only mojo.

R=darin
NOTRY=True

Review URL: https://codereview.chromium.org/56973010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@233006 0039d316-1c4b-4281-b951-d872f2087c98

mojo/tools/mojob.sh

@@ -15,7 +15,7 @@
 cd "$(realpath "$(dirname "$0")")/../.."
 
 build() {
-  ninja -C "out/$1" || exit 1
+  ninja -C "out/$1" mojo || exit 1
 }
 
 unittests() {