debian: Add sub-package for libosmo-gsup-client

Change-Id: Iad227bb477d64da30dd6bfbbe1bd0c0a55be9474
diff --git a/debian/libosmo-gsup-client0.install b/debian/libosmo-gsup-client0.install
new file mode 100644
index 0000000..78cd89f
--- /dev/null
+++ b/debian/libosmo-gsup-client0.install
@@ -0,0 +1 @@
+usr/lib/*/libosmo-gsup-client*.so.*