tools lib traceevent: Fix a risk for doing free on uninitialized pointer

Fix a risk of doing free on an uninitialized pointer.

This was found using a static code analysis program called cppcheck.
Acked-by: NNamhyung Kim <namhyung@kernel.org>
Signed-off-by: NRickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Link: http://lkml.kernel.org/r/1403608150-13037-1-git-send-email-rickard_strandqvist@spectrumdigital.seSigned-off-by: NJiri Olsa <jolsa@kernel.org>

tools/lib/traceevent/event-parse.c

@@ -2395,7 +2395,7 @@ process_flags(struct event_format *event, struct print_arg *arg, char **tok)
 {
 	struct print_arg *field;
 	enum event_type type;
-	char *token;
+	char *token = NULL;
 
 	memset(arg, 0, sizeof(*arg));
 	arg->type = PRINT_FLAGS;
@@ -2448,7 +2448,7 @@ process_symbols(struct event_format *event, struct print_arg *arg, char **tok)
 {
 	struct print_arg *field;
 	enum event_type type;
-	char *token;
+	char *token = NULL;
 
 	memset(arg, 0, sizeof(*arg));
 	arg->type = PRINT_SYMBOL;
@@ -2487,7 +2487,7 @@ process_hex(struct event_format *event, struct print_arg *arg, char **tok)
 {
 	struct print_arg *field;
 	enum event_type type;
-	char *token;
+	char *token = NULL;
 
 	memset(arg, 0, sizeof(*arg));
 	arg->type = PRINT_HEX;