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/util/FallbackRequestContext.java

@@ -37,7 +37,7 @@ public class FallbackRequestContext implements RequestContext {
   }
 
   @Override
-  public CurrentUser getCurrentUser() {
+  public CurrentUser getUser() {
     return user;
   }
 

gerrit-server/src/main/java/com/google/gerrit/server/util/ManualRequestContext.java

@@ -40,7 +40,7 @@ public class ManualRequestContext implements RequestContext, AutoCloseable {
   }
 
   @Override
-  public CurrentUser getCurrentUser() {
+  public CurrentUser getUser() {
     return user;
   }
 

gerrit-server/src/main/java/com/google/gerrit/server/util/PluginRequestContext.java

@@ -29,7 +29,7 @@ public class PluginRequestContext implements RequestContext {
   }
 
   @Override
-  public CurrentUser getCurrentUser() {
+  public CurrentUser getUser() {
     return user;
   }
 

gerrit-server/src/main/java/com/google/gerrit/server/util/RequestContext.java

@@ -23,6 +23,6 @@ import com.google.inject.Provider;
  * by the GerritGlobalModule scope.
  */
 public interface RequestContext {
-  CurrentUser getCurrentUser();
+  CurrentUser getUser();
   Provider<ReviewDb> getReviewDbProvider();
 }

gerrit-server/src/main/java/com/google/gerrit/server/util/RequestScopePropagator.java

@@ -188,8 +188,8 @@ public abstract class RequestScopePropagator {
       public T call() throws Exception {
         RequestContext old = local.setContext(new RequestContext() {
           @Override
-          public CurrentUser getCurrentUser() {
-            return context.getCurrentUser();
+          public CurrentUser getUser() {
+            return context.getUser();
           }
 
           @Override

gerrit-server/src/main/java/com/google/gerrit/server/util/ServerRequestContext.java

@@ -31,7 +31,7 @@ public class ServerRequestContext implements RequestContext {
   }
 
   @Override
-  public CurrentUser getCurrentUser() {
+  public CurrentUser getUser() {
     return user;
   }
 

gerrit-server/src/main/java/com/google/gerrit/server/util/ThreadLocalRequestContext.java

@@ -53,7 +53,7 @@ public class ThreadLocalRequestContext {
 
       @Provides
       CurrentUser provideCurrentUser(RequestContext ctx) {
-        return ctx.getCurrentUser();
+        return ctx.getUser();
       }
 
       @Provides