perf symbols: Demangle cloned functions

The libbfd C++ demangler doesn't seem to deal with cloned functions,
like symbol.clone.NUM.

Just strip the dot part before demangling and add it back later.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1378998998-10802-1-git-send-email-andi@firstfloor.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>