malloc fixes

Tor 0.2.1.15-rc marks the second release candidate for the 0.2.1.x
series. It fixes a major bug on fast exit relays, as well as a variety
of more minor bugs.

This is a release candidate! That means that we don't know of any
remaining show-stopping bugs, and this will become the new stable if
there are no problems. Please test it, and tell us about any problems
that you find. read more »