Default to building for the same architecture as the build host.
Default to building for the same architecture as the build host.

BUG=24766

Review URL: http://codereview.chromium.org/271113


git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@29230 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser