lib: Remove generated ovs-fields.7 manpage on make clean.
Found by travis.
Acked-by: Joe Stringer
-# Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016 Nicira, Inc.
+# Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 Nicira, Inc.
#
# Copying and distribution of this file, with or without modification,
# are permitted in any medium without royalty provided the copyright
@@ -539,6 +539,7 @@ lib-install-data-local:
$(MKDIR_P) $(DESTDIR)$(sysconfdir)/openvswitch
man_MANS += lib/ovs-fields.7
+CLEANFILES += lib/ovs-fields.7
lib/ovs-fields.7: $(srcdir)/build-aux/extract-ofp-fields include/openvswitch/meta-flow.h lib/meta-flow.xml
$(AM_V_GEN)PYTHONIOENCODING=utf8 $(run_python) $< \
--ovs-version=$(VERSION) ovs-fields \
