Remove gbp.conf, will not be using gbp to build deb package

Avoids updating it for every branch used to build it

debian/gbp.conf

@@ -1,18 +0,0 @@
-[DEFAULT]
-# Applies to all commands
-sign-tags = True
-
-# The default name for the upstream branch is "upstream".
-# Change it if the name is different (for instance, "master").
-upstream-branch = upstream
-
-# The default name for the Debian branch is "master".
-# Change it if the name is different (for instance, "debian/unstable").
-debian-branch = experimental
-
-# git-import-orig uses the following names for the upstream tags.
-# Change the value if you are not using git-import-orig
-upstream-tag = upstream/%(version)s
-
-# Always use pristine-tar.
-pristine-tar = True