ClangTools: Remove clang executable settings

We use custom clang executable and it does not make
sense anymore to give a choice of changing it.

Change-Id: Icf86042ac3fcd08c320ef2bbdaabef1102b023b5
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

src/plugins/clangrefactoring/clangrefactoring.qbs

@@ -25,6 +25,7 @@ QtcPlugin {
         var resourceDir = FileInfo.joinPaths(libclang.llvmLibDir, "clang", libclang.llvmVersion,
                                              "include");
         defines.push('CLANG_RESOURCE_DIR="' + resourceDir + '"');
+        defines.push('CLANG_BINDIR="' + libclang.llvmBinDir + '"');
         return defines;
     }