all: remove duplicated dependency (#5207)

Author: creamsoup

auth/build.gradle

@@ -3,7 +3,7 @@ dependencies {
     compile project(':grpc-core'),
             libraries.google_auth_credentials
     testCompile project(':grpc-testing'),
-            libraries.oauth_client
+            libraries.google_auth_oauth2_http
     signature "org.codehaus.mojo.signature:java17:1.0@signature"
     signature "net.sf.androidscents.signature:android-api-level-14:4.0_r4@signature"
 }

build.gradle

@@ -106,6 +106,7 @@ subprojects {
         javaPluginPath = "$rootDir/compiler/build/exe/java_plugin/$protocPluginBaseName$exeSuffix"
 
         nettyVersion = '4.1.32.Final'
+        googleauthVersion = '0.9.0'
         guavaVersion = '26.0-android'
         protobufVersion = '3.5.1'
         protocVersion = '3.5.1-1'
@@ -197,10 +198,9 @@ subprojects {
             hpack: 'com.twitter:hpack:0.10.1',
             javax_annotation: 'javax.annotation:javax.annotation-api:1.2',
             jsr305: 'com.google.code.findbugs:jsr305:3.0.2',
-            oauth_client: 'com.google.auth:google-auth-library-oauth2-http:0.9.0',
             google_api_protos: 'com.google.api.grpc:proto-google-common-protos:1.12.0',
-            google_auth_credentials: 'com.google.auth:google-auth-library-credentials:0.9.0',
-            google_auth_oauth2_http: 'com.google.auth:google-auth-library-oauth2-http:0.9.0',
+            google_auth_credentials: "com.google.auth:google-auth-library-credentials:${googleauthVersion}",
+            google_auth_oauth2_http: "com.google.auth:google-auth-library-oauth2-http:${googleauthVersion}",
             okhttp: 'com.squareup.okhttp:okhttp:2.5.0',
             okio: 'com.squareup.okio:okio:1.13.0',
             opencensus_api: "io.opencensus:opencensus-api:${opencensusVersion}",

interop-testing/build.gradle

@@ -21,9 +21,9 @@ dependencies {
             project(':grpc-protobuf'),
             project(':grpc-stub'),
             project(':grpc-testing'),
+            libraries.google_auth_oauth2_http,
             libraries.junit,
-            libraries.mockito,
-            libraries.oauth_client
+            libraries.mockito
     compile (libraries.truth) {
         // Disable because it uses Java 8 bytecode, which breaks gae-java7
         exclude group: 'com.google.auto.value', module: 'auto-value-annotations'