Merge pull request #18461 from taosdata/fix/coverity_alex

coverity problem fixed

source/os/src/osTimezone.c

@@ -744,9 +744,9 @@ void taosSetSystemTimezone(const char *inTimezoneStr, char *outTimezoneStr, int8
                            enum TdTimezone *tsTimezone) {
   if (inTimezoneStr == NULL || inTimezoneStr[0] == 0) return;
 
-  char *buf = taosMemoryMalloc(strlen(inTimezoneStr) + 1);
-  buf[strlen(inTimezoneStr)] = 0;
-  for (int32_t i = 0; i < strlen(inTimezoneStr); i++) {
+  size_t len = strlen(inTimezoneStr);
+  char  *buf = taosMemoryCalloc(len + 1, 1);
+  for (int32_t i = 0; i < len; i++) {
     if (inTimezoneStr[i] == ' ' || inTimezoneStr[i] == '(') {
       buf[i] = 0;
       break;