Clang: Fix qbs build

Broken with

  commit 9ad760ef
  Clang: Store the database in user resources

Change-Id: Idca0709e3e28291e43594f6b43f24faf7957a1a6
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp

@@ -35,8 +35,6 @@
 #include <refactoringdatabaseinitializer.h>
 #include <sqlitedatabase.h>
 
-#include <coreplugin/icore.h>
-
 #include <QCommandLineParser>
 #include <QCoreApplication>
 #include <QFileSystemWatcher>