I believe that since we were allocating *cp while holding a mutex,
coverity deduced that *cp must be protected by that mutex, and later
flipped out when we didn't use it that way. If this is so, we can
solve our problems by moving the *cp = tor_strdup(buf) part outside of
the mutex-protected code.
We do this in too many places throughout the code; it's time to start
clamping down.
Also, refactor Karsten's patch to use strchr-then-strndup, rather than
malloc-then-strlcpy-then-strchr-then-clear.
