Fix man page whatis entry errors

lintian says:
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man7/tc-hfsc.7.gz
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man8/ip-address.8.gz
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man8/ip-addrlabel.8.gz
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man8/ip-link.8.gz
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man8/ip-maddress.8.gz
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man8/ip-monitor.8.gz
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man8/ip-mroute.8.gz
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man8/ip-neighbour.8.gz
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man8/ip-netns.8.gz
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man8/ip-ntable.8.gz
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man8/ip-route.8.gz
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man8/ip-rule.8.gz
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man8/ip-tunnel.8.gz
W: iproute: manpage-has-bad-whatis-entry usr/share/man/man8/ip-xfrm.8.gz
14 files changed