Git: Fix order of arguments on branch diff

When there is a command in progress.

Change-Id: I73e8378283fcc34f324f862daaf2529b6a0f1265
Reviewed-by: André Hartmann <aha_1980@gmx.de>

src/plugins/git/gitclient.cpp

@@ -461,7 +461,7 @@ public:
     {
         setReloader([this, branch] {
             QStringList args = {"diff"};
-            args << addHeadWhenCommandInProgress() << branch;
+            args << branch << addHeadWhenCommandInProgress();
             runCommand({addConfigurationArguments(args)});
         });
     }