samples: Vision speech upgrade (#641)

* Fixes dependencies and class package changes.

* Guava exclusions so Truth doesn't conflict with Cloud Client

* Upgrades vision to 0.17.1

Author: gguuss

speech/snippets/src/main/java/com/example/speech/Recognize.java

@@ -16,7 +16,7 @@
 
 package com.example.speech;
 
-import com.google.api.gax.core.ApiStreamObserver;
+import com.google.api.gax.grpc.ApiStreamObserver;
 import com.google.api.gax.grpc.OperationFuture;
 import com.google.api.gax.grpc.StreamingCallable;
 import com.google.cloud.speech.spi.v1.SpeechClient;