Identify the OAuth provider as simply "GitHub"

As the provider name appears in the web page selection for the OAuth
provider, naming it as GitHub simplify the understanding of who is
actually authenticating the user.

The plugin name is indicated however as well after the provider name
it is then clear who is implementing the authentication.

Change-Id: I49c17104c1f692f8cc74dcee972797e9ea8928d9

github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/GitHubOAuthServiceProvider.java

diff --git a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/GitHubOAuthServiceProvider.java b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/GitHubOAuthServiceProvider.java
index 9e54c60..575ea11 100644
--- a/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/GitHubOAuthServiceProvider.java
+++ b/github-plugin/src/main/java/com/googlesource/gerrit/plugins/github/GitHubOAuthServiceProvider.java
@@ -39,15 +39,12 @@
 
   private final GitHubOAuthConfig config;
   private final OAuthProtocol oauth;
-  private final String name;
 
   @Inject
   public GitHubOAuthServiceProvider(GitHubOAuthConfig config,
-      OAuthProtocol oauth,
-      @PluginName String name) {
+      OAuthProtocol oauth) {
     this.config = config;
     this.oauth = oauth;
-    this.name = name;
   }
 
   @Override
@@ -83,6 +80,6 @@
 
   @Override
   public String getName() {
-    return name;
+    return "GitHub";
   }
 }