Add missing new file in MANIFEST

Needed for 'make rpmdev'

Signed-off-by: David Sommerseth <davids@redhat.com>

Author: David Sommerseth

MANIFEST

@@ -9,6 +9,7 @@ python-ethtool/etherinfo_ipv6_obj.c
 python-ethtool/etherinfo_struct.h
 python-ethtool/etherinfo.h
 python-ethtool/etherinfo_obj.h
+python-ethtool/netlink.c
 python-ethtool/netlink-address.c
 man/pethtool.8.asciidoc
 man/pifconfig.8.asciidoc