qcommon: fix potential buffer overflow in COM_StripFilename

Author: Exagone313

src/qcommon/q_shared.c

@@ -170,7 +170,7 @@ void COM_StripFilename(const char *in, char *out)
 {
 	char *end;
 
-	Q_strncpyz(out, in, strlen(in) + 1);
+	Q_strncpyz(out, in, MAX_QPATH);
 	end  = COM_SkipPath(out);
 	*end = 0;
 }