fix td-900: support both config dir & file

src/util/src/tconfig.c

@@ -308,11 +308,21 @@ bool taosReadGlobalCfg() {
 
   sprintf(fileName, "%s/taos.cfg", configDir);
   FILE* fp = fopen(fileName, "r");
+  if (fp == NULL) {
+    struct stat s;
+    if (stat(configDir, &s) != 0 || (!S_ISREG(s.st_mode) && !S_ISLNK(s.st_mode))) {
+      //return true to follow behavior before file support
+      return true;
+    }
+    fp = fopen(configDir, "r");
+    if (fp == NULL) {
+      return false;
+    }
+  }
   
   size_t len = 1024;
   line = calloc(1, len);
   
-  if (fp != NULL) {
   while (!feof(fp)) {
     memset(line, 0, len);
 
@@ -338,7 +348,6 @@ bool taosReadGlobalCfg() {
   }
 
   fclose(fp);
-  }
 
   tfree(line);