fix: throw on invalid credentials (#548)

Author: yoshi-automation

handwritten/firestore/dev/src/v1/firestore_client.js

@@ -178,10 +178,14 @@ class FirestoreClient {
     ];
     for (const methodName of firestoreStubMethods) {
       this._innerApiCalls[methodName] = gax.createApiCall(
-          firestoreStub.then(stub => function() {
-            const args = Array.prototype.slice.call(arguments, 0);
-            return stub[methodName].apply(stub, args);
-          }),
+          firestoreStub.then(
+              stub => function() {
+                const args = Array.prototype.slice.call(arguments, 0);
+                return stub[methodName].apply(stub, args);
+              },
+              err => function() {
+                throw err;
+              }),
           defaults[methodName],
           this._descriptors.page[methodName] ||
               this._descriptors.stream[methodName]);

handwritten/firestore/synth.metadata

@@ -1,19 +1,19 @@
 {
-  "updateTime": "2019-02-05T12:11:58.402Z",
+  "updateTime": "2019-02-13T12:15:47.405884Z",
   "sources": [
     {
       "generator": {
         "name": "artman",
-        "version": "0.16.9",
-        "dockerImage": "googleapis/artman@sha256:80c39fa84e7203c8f355e01bdeef82155013cc39dcaa48fba7a6fe2c253623e3"
+        "version": "0.16.13",
+        "dockerImage": "googleapis/artman@sha256:5fd9aee1d82a00cebf425c8fa431f5457539562f5867ad9c54370f0ec9a7ccaa"
       }
     },
     {
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "f26c727dde5051abefc5ad9e7dee82a2686ad2b0",
-        "internalRef": "232306662"
+        "sha": "ca61898878f0926dd9dcc68ba90764f17133efe4",
+        "internalRef": "233680013"
       }
     },
     {