fix(exists): properly handle errors

lib/api/exists.js

@@ -16,10 +16,18 @@ module.exports = function exists(path, cb) {
   var connection = this;
 
   SMB2Request('open', { path: path }, connection, function(err, file) {
-    if (err) cb && cb(null, false);
-    else
-      SMB2Request('close', file, connection, function() {
-        cb && cb(null, true);
-      });
+    if (err != null) {
+      if (
+        err.code === 'STATUS_OBJECT_NAME_NOT_FOUND' ||
+        err.code === 'STATUS_OBJECT_PATH_NOT_FOUND'
+      ) {
+        return cb && cb(null, false);
+      }
+      return cb && cb(err);
+    }
+
+    SMB2Request('close', file, connection, function() {
+      cb && cb(null, true);
+    });
   });
 };