contrib/git-credential-gnome-keyring.c: strlen() returns size_t, not …

…ssize_t

Also, initialization is not necessary since it is assigned before it is
used.

Signed-off-by: Brandon Casey <drafnel@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/credential/gnome-keyring/git-credential-gnome-keyring.c

@@ -306,7 +306,7 @@ static void credential_clear(struct credential *c)
 static int credential_read(struct credential *c)
 {
 	char    buf[1024];
-	ssize_t line_len = 0;
+	size_t line_len;
 	char   *key      = buf;
 	char   *value;