GitLab

Add IsBootPath to MountLibrary. Additional boot path check in imageburner so boot drive is not presented as a target.
BUG=chromium-os:6788
TEST=chrome://imageburner should not display /dev/sda

Review URL: http://codereview.chromium.org/6348006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@72733 0039d316-1c4b-4281-b951-d872f2087c98