perf annotate: Plug filename string leak

perf annotate: Plug filename string leak

If dso__build_id_filename(..., NULL, ...) returns !NULL its because it
allocated it, so, when reaching the  'if (dso__is_kcore()) test, we
already checked that and were just "fallbacking" to using
dso->long_name, but without freeing filename, thus leaking it.

Fix it by adding the dso__is_kcore() test to the 'or' group just after
it, the one containing the full fallback code, including freeing the
filename.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: ee205503f233 ("perf tools: Fix annotation with kcore")
Link: http://lkml.kernel.org/n/tip-qi4rpjq8yo6myvg99kkgt0xz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>