[nacltoons] Don't built with nacl-mounts by default
[nacltoons] Don't built with nacl-mounts by default

The bots don't have nacl-mounts installed, nor to they
build it as part of the game build anymore.

TEST=make all
BUG=None

Review URL: https://codereview.chromium.org/12316137

git-svn-id: e22621a84199d42b34715cdc089545aeedbbf23f@1512 050acbb0-2703-11df-ab0a-9f3f633ae91d

sbc100/nativeclient-sdk,sbc100/nativeclient-sdk,sbc100/nativeclient-sdk,sbc100/nativeclient-sdk,sbc100/nativeclient-sdk,sbc100/nativeclient-sdk,sbc100/nativeclient-sdk