qt.prf: add correct library version when using qmlimportscanner

We need to add the correct suffix to the libs we add when
running qmlimportscanner. Otherwise we will always add
release versions of the libs instead of debug versions
when generating debug builds. This in turn will confuse the
xcode generator that will try to convert the libs in
LIBS to native Xcode build variables.

Change-Id: I4d9fab49ad9e644e9bfd06caf79fc084bde2a3b7
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>

mkspecs/features/qt.prf

@@ -96,7 +96,7 @@ if(contains(QT, qml)|contains(QT_PRIVATE, qml)): \
         for (key, IMPORTS._KEYS_): {
             PATH = $$eval(IMPORTS.$${key}.path)
             PLUGIN = $$eval(IMPORTS.$${key}.plugin)
-            !isEmpty(PATH):!isEmpty(PLUGIN): LIBS *= -L$$PATH -l$$PLUGIN
+            !isEmpty(PATH):!isEmpty(PLUGIN): LIBS *= -L$$PATH -l$${PLUGIN}$$qtPlatformTargetSuffix()
         }
 
         # create qml_plugin_import.cpp