Remove shebang line from non-executable .py file.

Fixes checkperms failure on the main waterfall:

http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Full/builds/30316/steps/check_perms/logs/stdio
/b/build/slave/Linux_ChromiumOS/build/src/chrome/common/extensions/docs/server2/fake_host_file_system_provider.py: Has shebang but not executable bit

BUG=none
TBR=hukun@chromium.org,kalman@chromium.org

Review URL: https://codereview.chromium.org/113123007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242351 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242351