Set fixed size constraint on OWWidget if resizing_enabled flag is false.
Set fixed size constraint on OWWidget if resizing_enabled flag is false.

This should be consistent with the behaviour of
Qt.MSWindowsFixedSizeDialogHint window flag (which, as the name implies,
only works on Windows) passed to base widget constructor.

cheral/orange3,cheral/orange3,kwikadi/orange3,marinkaz/orange3,qPCR4vir/orange3,cheral/orange3,qPCR4vir/orange3,qPCR4vir/orange3,marinkaz/orange3,kwikadi/orange3,marinkaz/orange3,kwikadi/orange3,cheral/orange3,kwikadi/orange3,kwikadi/orange3,marinkaz/orange3,qPCR4vir/orange3,marinkaz/orange3,kwikadi/orange3,marinkaz/orange3,qPCR4vir/orange3,cheral/orange3,cheral/orange3,qPCR4vir/orange3