python.port.mk: Change indentation to make reading easier

The end of python.port.mk had two ".endif". It took a bit of tracing and
I figured out the final one closed ".if empty(CONFIGURE_STYLE)".

Except for the ".if make (update-plist) || make(plist)", the .ifs are
indented to indicate they are nested. This patch just indents the logic
that throws a warning about making a PLIST without FLAVOR=python3.

It makes it easier to read.

OK?

--Kurt

Index: python.port.mk
===================================================================
RCS file: /cvs/ports/lang/python/python.port.mk,v
retrieving revision 1.114
diff -u -p -r1.114 python.port.mk
--- python.port.mk 24 Jun 2019 14:25:54 -0000 1.114
+++ python.port.mk 24 Sep 2019 17:41:59 -0000
@@ -239,10 +239,10 @@ do-test:
@${MODPY_TEST_TARGET}
. endif

-.if make(update-plist) || make(plist)
-. if defined(FLAVORS) && ${FLAVORS:Mpython3} && !${FLAVOR:Mpython3}
+. if make(update-plist) || make(plist)
+. if defined(FLAVORS) && ${FLAVORS:Mpython3} && !${FLAVOR:Mpython3}
ERRORS += "***\n*** WARNING: running update-plist without FLAVOR=python3\n***\n***"
+. endif
. endif
-.endif

.endif