Bump the GAX version (googleapis#1688)

* Bump the GAX version
* Update spanner GAX version

Author: michaelbausor

google-cloud-spanner/pom.xml

@@ -129,7 +129,7 @@
     <dependency>
       <groupId>com.google.api</groupId>
       <artifactId>gax</artifactId>
-      <version>0.0.25</version>
+      <version>${gax.version}</version>
       <exclusions>
         <exclusion>
           <groupId>io.grpc</groupId>

pom.xml

@@ -92,7 +92,7 @@
     <github.global.server>github</github.global.server>
     <google.auth.version>0.6.0</google.auth.version>
     <grpc.version>1.0.3</grpc.version>
-    <gax.version>0.1.2</gax.version>
+    <gax.version>0.1.4</gax.version>
     <generatedProto.version>0.1.5</generatedProto.version>
     <core.version>0.9.4-alpha-SNAPSHOT</core.version>
     <beta.version>0.9.4-beta-SNAPSHOT</beta.version>