Add --purge FILE to remove all caches of FILE.

Since the current --remove FILE removes a cache which has
same build-id of given FILE. Since the command takes a
FILE path, it can confuse user who tries to remove cache
about FILE path.

  -----
  # ./perf buildid-cache -v --add ./perf
  Adding 133b7b5486d987a5ab5c3ebf4ea14941f45d4d4f ./perf: Ok
  # (update the ./perf binary)
  # ./perf buildid-cache -v --remove ./perf
  Removing 305bbd1be68f66eca7e2d78db294653031edfa79 ./perf: FAIL
  ./perf wasn't in the cache
  -----
Actually, the --remove's FAIL is not shown, it just silently fails.

So, this patch adds --purge FILE action for such usecase.

perf buildid-cache --purge FILE removes all caches which has same FILE
path.

In other words, it removes all caches including old binaries.

  -----
  # ./perf buildid-cache -v --add ./perf
  Adding 133b7b5486d987a5ab5c3ebf4ea14941f45d4d4f ./perf: Ok
  # (update the ./perf binary)
  # ./perf buildid-cache -v --purge ./perf
  Removing 133b7b5486d987a5ab5c3ebf4ea14941f45d4d4f ./perf: Ok
  -----

BTW, if you want to purge all the caches, remove ~/.debug/* .
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20150227045026.1999.64084.stgit@localhost.localdomain
[ s/dirname/dir_name/g to fix build on fedora14, where dirname is a global ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>