perf probe: Add missing variable initialization

cc1: warnings being treated as errors
 util/probe-finder.c: In function 'find_line_range':
 util/probe-finder.c:172: warning: 'src' may be used
 uninitialized in this function make: *** [util/probe-finder.o]
 Error 1

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1267804269-22660-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/util/probe-finder.c

@@ -169,7 +169,7 @@ static const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname)
 {
 	Dwarf_Files *files;
 	size_t nfiles, i;
-	const char *src;
+	const char *src = NULL;
 	int ret;
 
 	if (!fname)