fix: throw on invalid credentials (#418)

Author: yoshi-automation

handwritten/bigtable/src/v2/bigtable_client.js

@@ -150,6 +150,10 @@ class BigtableClient {
             function() {
               const args = Array.prototype.slice.call(arguments, 0);
               return stub[methodName].apply(stub, args);
+            },
+          err =>
+            function() {
+              throw err;
             }
         ),
         defaults[methodName],

handwritten/bigtable/synth.metadata

@@ -1,19 +1,19 @@
 {
-  "updateTime": "2019-01-25T12:09:11.464153Z",
+  "updateTime": "2019-02-13T12:10:12.075104Z",
   "sources": [
     {
       "generator": {
         "name": "artman",
-        "version": "0.16.7",
-        "dockerImage": "googleapis/artman@sha256:d6c8ced606eb49973ca95d2af7c55a681acc042db0f87d135968349e7bf6dd80"
+        "version": "0.16.13",
+        "dockerImage": "googleapis/artman@sha256:5fd9aee1d82a00cebf425c8fa431f5457539562f5867ad9c54370f0ec9a7ccaa"
       }
     },
     {
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "9aac88a22468b1e291937f55fa1ef237adfdc63e",
-        "internalRef": "230568136"
+        "sha": "ca61898878f0926dd9dcc68ba90764f17133efe4",
+        "internalRef": "233680013"
       }
     },
     {