[tracker] libtracker-extract (tracker_date_guess): Protect against invalid values.

[Carlos Garnacho <carlosg src gnome org>]

commit 6f2be878702cd5a82d5f20d986ae648c4027e06d
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue May 4 15:37:12 2010 +0200

    libtracker-extract (tracker_date_guess): Protect against invalid values.

 src/libtracker-extract/tracker-utils.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/src/libtracker-extract/tracker-utils.c b/src/libtracker-extract/tracker-utils.c
index 11600bc..a2cc6ab 100644
--- a/src/libtracker-extract/tracker-utils.c
+++ b/src/libtracker-extract/tracker-utils.c
@@ -648,6 +648,10 @@ tracker_date_guess (const gchar *date_string)
 
 		num_month = parse_month (date_string + 4);
 
+		if (num_month < 0) {
+			return NULL;
+		}
+
 		mon1 = imonths[num_month];
 
 		if (date_string[8] == ' ') {