www/pelican - add TEST_ENV for tests

While doing my testing for py-dateutil I noticed pelican started failing
more tests. In my investigation I noticed the Makefile set LC_CTYPE
in MAKE_ENV. So I added the same to TEST_ENV and suddenly the test results
for py-dateutil 2.8.0 matched those with py-dateutil 2.7.3.

So here's a diff for the addition to TEST_ENV.

--Kurt

Index: Makefile
===================================================================
RCS file: /cvs/ports/www/pelican/Makefile,v
retrieving revision 1.9
diff -u -p -r1.9 Makefile
--- Makefile 25 Nov 2018 19:57:14 -0000 1.9
+++ Makefile 3 Mar 2019 05:34:57 -0000
@@ -37,6 +37,8 @@ RUN_DEPENDS = devel/py-blinker${MODPY_F
# Else setuptools skips filenames containing UTF8 chars
MAKE_ENV += LC_CTYPE=en_US.UTF-8

+TEST_ENV += LC_CTYPE=en_US.UTF-8
+
TEST_DEPENDS = ${RUN_DEPENDS} \
devel/git \
devel/py-mock${MODPY_FLAVOR}