external/python3: Drop nis.cpython-*m.so

At least Fedora 28 glibc-2.27-8.fc28 no longer provides the nis development
headers and libraries.  (It only still contains some binaries for backwards
compatibility, in the libnsl sub-package: "This package provides the legacy
version of libnsl library, for accessing NIS services.")

There is probably no real need to have nis.cpython-*m.so contained in
external/python3/ExternalPackage_python3.mk (it probably just happened to build
fine when that list was originally created, so was included).

Change-Id: Ic6128fd872432005c0ded76640c5b56781ca69a1
Reviewed-on: https://gerrit.libreoffice.org/52535Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

external/python3/ExternalPackage_python3.mk

@@ -83,7 +83,6 @@ $(eval $(call gb_ExternalPackage_add_files,python3,$(LIBO_BIN_FOLDER)/python-cor
 	LO_lib/mmap.cpython-$(PYTHON_VERSION_MAJOR).$(PYTHON_VERSION_MINOR)m.so \
 	LO_lib/_multibytecodec.cpython-$(PYTHON_VERSION_MAJOR).$(PYTHON_VERSION_MINOR)m.so \
 	LO_lib/_multiprocessing.cpython-$(PYTHON_VERSION_MAJOR).$(PYTHON_VERSION_MINOR)m.so \
-	LO_lib/nis.cpython-$(PYTHON_VERSION_MAJOR).$(PYTHON_VERSION_MINOR)m.so \
 	LO_lib/_opcode.cpython-$(PYTHON_VERSION_MAJOR).$(PYTHON_VERSION_MINOR)m.so \
 	LO_lib/ossaudiodev.cpython-$(PYTHON_VERSION_MAJOR).$(PYTHON_VERSION_MINOR)m.so \
 	LO_lib/parser.cpython-$(PYTHON_VERSION_MAJOR).$(PYTHON_VERSION_MINOR)m.so \