Sometimes people use the old github-style 'clone http://host/whatever.git'.

We don't want the destination dir to be named whatever.git in this
case.

Auditors: chris

Test plan:
Fingers crossed
Fix culture-cow to cd back to the rootdir when it's done.

Ah, the things we find when we actually *run* the script...

Auditors: chris

Test plan:
Fingers crossed