Use localtime() to format time_t in cvtTimeToZ().

Using gmtime() produced output skewed by the local timezone.

Since this function is currently only used for debug logging this is not a live bug in the field.

src/common/type/convert.c

@@ -395,7 +395,7 @@ cvtTimeToZ(time_t value, char *buffer, size_t bufferSize)
 
     ASSERT(buffer != NULL);
 
-    size_t result = strftime(buffer, bufferSize, "%s", gmtime(&value));
+    size_t result = strftime(buffer, bufferSize, "%s", localtime(&value));
 
     if (result == 0)
         THROW(AssertError, "buffer overflow");