debian: build manuals as osmo-remsim-doc package

Change-Id: If5812983d319a32864f5f34b160978533465d185
diff --git a/debian/rules b/debian/rules
index bbf2626..a36fe36 100755
--- a/debian/rules
+++ b/debian/rules
@@ -12,7 +12,7 @@
 	dh $@ --with=systemd --with autoreconf --fail-missing
 
 override_dh_auto_configure:
-	dh_auto_configure --  --with-systemdsystemunitdir=/lib/systemd/system
+	dh_auto_configure --  --with-systemdsystemunitdir=/lib/systemd/system --enable-manuals
 
 #override_dh_clean:
 #	dh_clean