Rename getCurrentUser to getUser

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

Change-Id: I03a051f1fd3758ba63749cded20a7c135b6cf58a

gerrit-server/src/main/java/com/google/gerrit/server/account/CapabilityControl.java

@@ -58,7 +58,7 @@ public class CapabilityControl {
   }
 
   /** Identity of the user the control will compute for. */
-  public CurrentUser getCurrentUser() {
+  public CurrentUser getUser() {
     return user;
   }