Remove misleading use of KDE_INSTALL_PYTHONBINDINGSDIR

Summary:
Removing the (typically empty) optional argument from the function
invocation avoids confusion and allows to remove the parameter.

See also D15558

Test Plan: make

Reviewers: #frameworks, apol

Subscribers: kde-frameworks-devel

Tags: #frameworks

Differential Revision: https://phabricator.kde.org/D15848

src/core/CMakeLists.txt

@@ -56,7 +56,6 @@ if (PythonModuleGeneration_FOUND)
     PYTHONNAMESPACE PyKF5
     MODULENAME KConfigCore
     RULES_FILE "${CMAKE_SOURCE_DIR}/cmake/rules_PyKF5.py"
-    INSTALL_DIR_SUFFIX ${KDE_INSTALL_PYTHONBINDINGSDIR}
     SIP_DEPENDS
       QtCore/QtCoremod.sip
     HEADERS

src/gui/CMakeLists.txt

@@ -40,7 +40,6 @@ if (PythonModuleGeneration_FOUND)
     PYTHONNAMESPACE PyKF5
     MODULENAME KConfigGui
     RULES_FILE "${CMAKE_SOURCE_DIR}/cmake/rules_PyKF5.py"
-    INSTALL_DIR_SUFFIX ${KDE_INSTALL_PYTHONBINDINGSDIR}
     SIP_INCLUDES
       "${CMAKE_BINARY_DIR}/src/core/sip"
     SIP_DEPENDS