build: fix dist tarball

automake file lists haven't quite kept up with recent changes, time to
fix them up so the dist tarball actually works...

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/Makefile.am b/Makefile.am
index 8371041..37fea43 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -12,7 +12,8 @@
 	update-autotools \
 	vtysh/Makefile.in vtysh/Makefile.am \
 	tools/mrlg.cgi tools/rrcheck.pl tools/rrlookup.pl tools/zc.pl \
-	tools/zebra.el tools/multiple-bgpd.sh
+	tools/zebra.el tools/multiple-bgpd.sh \
+	fpm/fpm.h
 
 if HAVE_LATEX