perf symbols: Rename [sl]name_alloc to match the members they refer to

perf symbols: Rename [sl]name_alloc to match the members they refer to

So we now have:

   dso->short_name
   dso->short_name_len
   dso->short_name_allocated

Ditto for the 'long  variants. To more quickly grasp what they refer to.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-nu228f8vlp9w0lr7c0q77dqi@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>