perf machine: Fix path unpopulated in machine__create_modules()

In machine__create_modules() the 'path' char array was used in a call to
symbol__restricted_filename() without always being populated.

Signed-off-by: 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@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1379845338-29637-2-git-send-email-adrian.hunter@intel.com
[ Split patch removing unrelated conversion of sprintf to snprintf to perf/core ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>