fix(rmdir): dont test existence

Test pre-condition can leads to race-conditions.
Also current code was hiding SMB error.

lib/api/rmdir.js

@@ -18,37 +18,27 @@ var SMB2Forge = require('../tools/smb2-forge'),
 module.exports = function rmdir(path, cb) {
   var connection = this;
 
-  connection.exists(path, function(err, exists) {
+  // SMB2 open file
+  SMB2Request('open_folder', { path: path }, connection, function(err, file) {
     if (err) cb && cb(err);
-    else if (exists) {
-      // SMB2 open file
-      SMB2Request('open_folder', { path: path }, connection, function(
-        err,
-        file
-      ) {
-        if (err) cb && cb(err);
-        // SMB2 query directory
-        else
-          SMB2Request(
-            'set_info',
-            {
-              FileId: file.FileId,
-              FileInfoClass: 'FileDispositionInformation',
-              Buffer: new bigint(1, 1).toBuffer(),
-            },
-            connection,
-            function(err, files) {
-              if (err) cb && cb(err);
-              // SMB2 close directory
-              else
-                SMB2Request('close', file, connection, function() {
-                  cb && cb(null, files);
-                });
-            }
-          );
-      });
-    } else {
-      cb(new Error('Folder does not exists'));
-    }
+    // SMB2 query directory
+    else
+      SMB2Request(
+        'set_info',
+        {
+          FileId: file.FileId,
+          FileInfoClass: 'FileDispositionInformation',
+          Buffer: new bigint(1, 1).toBuffer(),
+        },
+        connection,
+        function(err, files) {
+          if (err) cb && cb(err);
+          // SMB2 close directory
+          else
+            SMB2Request('close', file, connection, function() {
+              cb && cb(null, files);
+            });
+        }
+      );
   });
 };