Sync: Add HTTP Cookie File header on temporary cookie file

The .gitcookies file generated by does not have
the header:

 # (Netscape) HTTP Cookie File

which causes python's MozillaCookieJar.load to fail with the

 "does not look like a Netscape format cookies file"

Prepend the expected header onto the generated cookie file.

We don't bother to check if the header already exists on the
file; repeating it does not cause any problem.

Bug: Issue 207
Change-Id: I7d39720a1d36a6aae00f70691156514ebc04e579
1 file changed