CMakePM: Do not use displayName for build directory

This code path was used when adding a new build type from settings via
Add -> RelWithDebInfo and it would be expanded to "Release-with-Debug-
Information".

On Windows this can lead to long paths and problems.

Change-Id: Ie6ab74414778a2e723bfa08d6765292dfe6bce22
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp

@@ -1304,7 +1304,7 @@ CMakeBuildConfiguration::CMakeBuildConfiguration(Target *target, Id id)
         if (info.buildDirectory.isEmpty()) {
             setBuildDirectory(shadowBuildDirectory(target->project()->projectFilePath(),
                                                    k,
-                                                   info.displayName,
+                                                   info.typeName,
                                                    info.buildType));
         }