Rename getCurrentUser to getUser

It is never ambiguous to say "User" instead of "CurrentUser". Save
some typing.

Change-Id: I03a051f1fd3758ba63749cded20a7c135b6cf58a

gerrit-gpg/src/test/java/com/google/gerrit/gpg/GerritPublicKeyCheckerTest.java

@@ -126,7 +126,7 @@ public class GerritPublicKeyCheckerTest {
 
     requestContext.setContext(new RequestContext() {
       @Override
-      public CurrentUser getCurrentUser() {
+      public CurrentUser getUser() {
         return user;
       }