QbsPM: Re-introduce uniqueProductName()

This patch prepares for enhancing information stored inside
buildSystemTarget.

Change-Id: I5d81fd01ab6b06c162f47fd9536de697ddfd24a3
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

src/plugins/qbsprojectmanager/qbsproject.cpp

@@ -955,7 +955,7 @@ void QbsProject::updateCppCodeModel()
             rpp.setDisplayName(grp.name());
             rpp.setProjectFileLocation(grp.location().filePath(),
                                        grp.location().line(), grp.location().column());
-            rpp.setBuildSystemTarget(uniqueProductName(prd));
+            rpp.setBuildSystemTarget(prd.name());
 
             QHash<QString, qbs::ArtifactData> filePathToSourceArtifact;
             bool hasCFiles = false;