Relative paths for auth cookie
The COOKIEFILE attribute of PROTOCOLINFO responses are relative when we don't have an absolute path for our data directory. This is the case with TBB which is very problematic for controllers (vidalia only works because it shares the same working directory).
Section 3.21 of the control-spec specifies that the COOKIEFILE attribute is an absolute path so this is definitely a bug.
This is being moved from... https://trac.torproject.org/projects/tor/ticket/1101