Ignore .deb build byproducts

Change-Id: Iec63ef5ea0acfc5e6621054926be15ae4754d65d
diff --git a/.gitignore b/.gitignore
index 507ee62..12f3c4a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -82,3 +82,7 @@
 doc/manuals/vty/ggsn_vty_reference.xml
 
 contrib/osmo-ggsn.spec
+/debian/gtp-echo-responder-dbg/
+/debian/gtp-echo-responder/
+/debian/osmo-ggsn-doc/
+/utils/gtp-echo-responder