cmds/cosd: Fix IsHeapProfilerRunning implicit return type cast.

cmds/cosd: Fix IsHeapProfilerRunning implicit return type cast.

G++ complains about the difference between the return type of tcmalloc's
IsHeapProfilerRunning (int) and the return type of the function that
g_conf.profiler_running is supposed to point to (bool). We could
probably get away with a type-cast, but as a compiler developer and
former C++ language lawyer, I'd rather not take the risk of destroying
the universe by invoking undefined behavior ;-)

Signed-off-by: Alexandre Oliva <oliva@lsd.ic.unicamp.br>
Signed-off-by: Greg Farnum <gregory.farnum@dreamhost.com>