find features/ under mkspecs/ of source & build root
find features/ under mkspecs/ of source & build root

we were finding features/ directly in the source & build root, and we
were finding features/ under mkspecs/ from $QMAKEPATH and other mkspecs
locations, but we omitted the "transitive hull". this was
counterintuitive.

Change-Id: I9823e6606467c98f264c81385250da92311f51ca
(cherry picked from qtbase/0bf65180b8710e4516496d0bc53a265ff0dd6a01)
Reviewed-by: Daniel Teske <d8a411aec9a206efedb4d45b75fe8d13f1e2b628@digia.com>

Distrotech/qtcreator,Distrotech/qtcreator,danimo/qt-creator,darksylinc/qt-creator,AltarBeastiful/qt-creator,xianian/qt-creator,martyone/sailfish-qtcreator,richardmg/qtcreator,colede/qtcreator,malikcjm/qtcreator,maui-packages/qt-creator,amyvmiwei/qt-creator,colede/qtcreator,duythanhphan/qt-creator,richardmg/qtcreator,AltarBeastiful/qt-creator,xianian/qt-creator,darksylinc/qt-creator,kuba1/qtcreator,farseerri/git_code,danimo/qt-creator,maui-packages/qt-creator,kuba1/qtcreator,Distrotech/qtcreator,darksylinc/qt-creator,maui-packages/qt-creator,farseerri/git_code,malikcjm/qtcreator,farseerri/git_code,maui-packages/qt-creator,kuba1/qtcreator,AltarBeastiful/qt-creator,farseerri/git_code,danimo/qt-creator,amyvmiwei/qt-creator,Distrotech/qtcreator,omniacreator/qtcreator,danimo/qt-creator,Distrotech/qtcreator,kuba1/qtcreator,amyvmiwei/qt-creator,xianian/qt-creator,richardmg/qtcreator,amyvmiwei/qt-creator,martyone/sailfish-qtcreator,omniacreator/qtcreator,AltarBeastiful/qt-creator,xianian/qt-creator,martyone/sailfish-qtcreator,malikcjm/qtcreator,duythanhphan/qt-creator,omniacreator/qtcreator,farseerri/git_code,xianian/qt-creator,kuba1/qtcreator,duythanhphan/qt-creator,martyone/sailfish-qtcreator,AltarBeastiful/qt-creator,richardmg/qtcreator,omniacreator/qtcreator,danimo/qt-creator,martyone/sailfish-qtcreator,richardmg/qtcreator,Distrotech/qtcreator,kuba1/qtcreator,maui-packages/qt-creator,xianian/qt-creator,martyone/sailfish-qtcreator,maui-packages/qt-creator,xianian/qt-creator,malikcjm/qtcreator,colede/qtcreator,darksylinc/qt-creator,darksylinc/qt-creator,darksylinc/qt-creator,AltarBeastiful/qt-creator,omniacreator/qtcreator,kuba1/qtcreator,martyone/sailfish-qtcreator,colede/qtcreator,martyone/sailfish-qtcreator,malikcjm/qtcreator,AltarBeastiful/qt-creator,farseerri/git_code,kuba1/qtcreator,colede/qtcreator,duythanhphan/qt-creator,danimo/qt-creator,maui-packages/qt-creator,richardmg/qtcreator,omniacreator/qtcreator,amyvmiwei/qt-creator,duythanhphan/qt-creator,omniacreator/qtcreator,danimo/qt-creator,richardmg/qtcreator,malikcjm/qtcreator,duythanhphan/qt-creator,colede/qtcreator,AltarBeastiful/qt-creator,xianian/qt-creator,Distrotech/qtcreator,farseerri/git_code,duythanhphan/qt-creator,danimo/qt-creator,kuba1/qtcreator,xianian/qt-creator,amyvmiwei/qt-creator,malikcjm/qtcreator,amyvmiwei/qt-creator,darksylinc/qt-creator,martyone/sailfish-qtcreator,colede/qtcreator,amyvmiwei/qt-creator,darksylinc/qt-creator,farseerri/git_code,danimo/qt-creator