precise/trusty: don't attempt to install pimd or ldpd manuals

Neither of these daemons are installed on 14.04, leading to build
failures now that the man pages are excluded from the Makefiles when
the daemons aren't enabled for install.

Signed-off-by: Silas McCroskey <smccroskey@cumulusnetworks.com>

debian/backports/ubuntu14.04/debian/frr.install

@@ -15,8 +15,6 @@ usr/share/man/man8/ripd.8
 usr/share/man/man8/ripngd.8
 usr/share/man/man8/zebra.8
 usr/share/man/man8/isisd.8
-usr/share/man/man8/pimd.8
-usr/share/man/man8/ldpd.8
 usr/share/man/man8/watchfrr.8
 usr/share/snmp/mibs/
 cumulus/etc/* etc/