Fix documentation that labels for logging entry has to be STRING (#1241)

Author: faithseed

README.md

@@ -475,7 +475,7 @@ var resource = {
   type: 'gce_instance',
   labels: {
     zone: 'global',
-    instance_id: 3
+    instance_id: '3'
   }
 };
 

lib/logging/entry.js

@@ -57,7 +57,7 @@ var GrpcService = require('../common/grpc-service.js');
  *   type: 'gce_instance',
  *   labels: {
  *     zone: 'global',
- *     instance_id: 3
+ *     instance_id: '3'
  *   }
  * };
  *

lib/logging/index.js

@@ -255,7 +255,7 @@ Logging.prototype.createSink = function(name, config, callback) {
  *   type: 'gce_instance',
  *   labels: {
  *     zone: 'global',
- *     instance_id: 3
+ *     instance_id: '3'
  *   }
  * };
  *
@@ -269,7 +269,7 @@ Logging.prototype.createSink = function(name, config, callback) {
  * //     type: 'gce_instance',
  * //     labels: {
  * //       zone: 'global',
- * //       instance_id: 3
+ * //       instance_id: '3'
  * //     }
  * //   },
  * //   jsonPayload: {

lib/logging/log.js

@@ -226,7 +226,7 @@ Log.prototype.emergency = function(entry, options, callback) {
  *   type: 'gce_instance',
  *   labels: {
  *     zone: 'global',
- *     instance_id: 3
+ *     instance_id: '3'
  *   }
  * };
  *
@@ -241,7 +241,7 @@ Log.prototype.emergency = function(entry, options, callback) {
  * //     type: 'gce_instance',
  * //     labels: {
  * //       zone: 'global',
- * //       instance_id: 3
+ * //       instance_id: '3'
  * //     }
  * //   },
  * //   jsonPayload: {