windows mod_enum fix potential seg

src/mod/applications/mod_enum/mod_enum.c

@@ -153,14 +153,12 @@ static switch_status_t load_config(void)
 			"SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters", 
 			0, KEY_QUERY_VALUE, &hKey);
 
+		if (hKey) {
 			RegQueryValueEx(hKey, "DhcpNameServer", NULL, NULL, NULL, &data_sz);
-		if (globals.server) {
-			free(globals.server);
-		}
+			if (data_sz) {
 				buf = (char*)malloc(data_sz + 1);
 
 				RegQueryValueEx(hKey, "DhcpNameServer", NULL, NULL, (LPBYTE)buf, &data_sz);
-
 				RegCloseKey(hKey);
 
 				if(buf[data_sz - 1] != 0) {
@@ -168,6 +166,8 @@ static switch_status_t load_config(void)
 				}
 				globals.server = buf;
 			}
+		}
+	}
 #endif