Set the save file type index properly if there was only one file type.

The save file indexes are 1 based, and if there is only one file type
that the page can be saved as (such as a page like foo.com/notes.txt),
the index is set to 0 which will cause a crash.

BUG=15555 (http://crbug.com/15555)
TEST=Go to a web page that is a text file and try to save it. Chrome
     should not crash.

Review URL: http://codereview.chromium.org/155264

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@20293 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed