QmakeProjectManager: Remove python file type

This is a partial regression from b503ea7f06.

The main goal was just to have an overlay on the Python files,
but since qmake and python don't really interact, adding a new
FileType triggered all the contents from "Other sources" to
be duplicated in the "Python sources" node.

The Python sources node is not necessary at the moment,
so I remove it to avoid duplicated tree elements.

Change-Id: I61e9e51327689636328a746059159c962270e805
Fixes: QTCREATORBUG-22292
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/projectexplorer/projectnodes.h

@@ -49,7 +49,6 @@ enum class FileType : quint16 {
     Unknown = 0,
     Header,
     Source,
-    PythonSource,
     Form,
     StateChart,
     Resource,

src/plugins/qmakeprojectmanager/qmakenodetreebuilder.cpp

@@ -61,8 +61,6 @@ const FileTypeDataStorage fileTypeDataStorage[] = {
       ProjectExplorer::Constants::FILEOVERLAY_H, "*.h; *.hh; *.hpp; *.hxx;"},
     { FileType::Source, QT_TRANSLATE_NOOP("QmakeProjectManager::QmakePriFile", "Sources"),
       ProjectExplorer::Constants::FILEOVERLAY_CPP, "*.c; *.cc; *.cpp; *.cp; *.cxx; *.c++;" },
-    { FileType::PythonSource, QT_TRANSLATE_NOOP("QmakeProjectManager::QmakePriFile", "Python sources"),
-      ProjectExplorer::Constants::FILEOVERLAY_PY, "*.py;" },
     { FileType::Form, QT_TRANSLATE_NOOP("QmakeProjectManager::QmakePriFile", "Forms"),
       ProjectExplorer::Constants::FILEOVERLAY_UI, "*.ui;" },
     { FileType::StateChart, QT_TRANSLATE_NOOP("QmakeProjectManager::QmakePriFile", "State charts"),