[wip/ros18-base] Kill SUBST_STAGE definition for replacing python interpreter

These rules are now provided directly by sysdep/python.mk

ros18-base/Makefile.common

@@ -45,12 +45,6 @@ SUBST_STAGE.bash-interp=pre-configure
 SUBST_MESSAGE.bash-interp=Replacing bash interpreter path
 SUBST_SED.bash-interp=	-e '1s|^\\\#!.*bash|\\\#!${BASH}|'
 
-# Replace python interpreter
-SUBST_STAGE.py-interp=	pre-configure
-SUBST_MESSAGE.py-interp=Replacing python interpreter path
-SUBST_SED.py-interp=	-e '1s|^\\\#!.*python[0-9.]*|\\\#!${PYTHON}|'
-SUBST_SED.py-interp+=	-e 's|@PYTHON@|${PYTHON}|'
-
 # Add PYTHON_SITELIB to sys.path
 SUBST_STAGE.py-syspath=	pre-configure
 SUBST_MESSAGE.py-syspath=Configuring sys.path in python scripts