[libcalamares] Don't link with PythonQt

- PythonQt is only needed (and used) from the GUI library.

CHANGES

@@ -9,6 +9,10 @@ This release contains contributions from (alphabetically by first name):
 
 ## Core ##
 
+ - *libcalamares* (accidentally) linked with Qt's GUI libraries when
+   PythonQt was found. This led to the odd situation where the non-GUI
+   Calamares library depends on a bunch of GUI libraries.
+
 ## Modules ##
 
  - All Python modules now bail out gracefully on (at least some) bad
@@ -16,6 +20,7 @@ This release contains contributions from (alphabetically by first name):
    scripts now test for exceptions to avoid shipping modules with
    ImportError or SyntaxError results.
 
+
 # 3.2.7 (2019-04-27) #
 
 This is a **hotfix** release for regressions introduced in the

src/libcalamares/CMakeLists.txt

@@ -67,21 +67,6 @@ if( WITH_PYTHON )
     )
 endif()
 
-if( WITH_PYTHONQT )
-    include_directories(${PYTHON_INCLUDE_DIRS})
-    link_directories(${PYTHON_LIBRARIES})
-
-    include_directories(${PYTHONQT_INCLUDE_DIR})
-    link_directories(${PYTHONQT_LIBRARY})
-
-    set( OPTIONAL_PRIVATE_LIBRARIES
-        ${OPTIONAL_PRIVATE_LIBRARIES}
-        ${PYTHON_LIBRARIES}
-        ${PYTHONQT_LIBRARY}
-    )
-endif()
-
-
 add_library( calamares SHARED ${libSources} ${kdsagSources} ${utilsSources} )
 set_target_properties( calamares
     PROPERTIES