Correctly fix the Python 3 being the default but in fact not problem.

Sponsored by:	Absolight

Mk/Uses/python.mk

@@ -428,10 +428,10 @@ _ALL_PYTHON_FLAVORS=	${_PYTHON_VERSIONS:S/.//:S/^/py/}
 .  if defined(BUILD_ALL_PYTHON_FLAVORS) || defined(_PYTHON_FEATURE_ALLFLAVORS)
 FLAVORS=	${_ALL_PYTHON_FLAVORS}
 .  else
-.    for _v in ${PYTHON3_DEFAULT} ${PYTHON2_DEFAULT} ${PYTHON_DEFAULT}
+.    for _v in ${PYTHON_DEFAULT} ${PYTHON2_DEFAULT} ${PYTHON3_DEFAULT}
 _f=	py${_v:S/.//}
-.      if ${_ALL_PYTHON_FLAVORS:M${_f}}
-FLAVORS:=	${_f} ${FLAVORS:N${_f}}
+.      if ${_ALL_PYTHON_FLAVORS:M${_f}} && !${FLAVORS:M${_f}}
+FLAVORS:=	${FLAVORS} ${_f}
 .      endif
 .    endfor
 .  endif