Update .gitignore: ignore osmo-euse-demo

Change-Id: I1e2fb003d507a00f9255e021dd8956269f0657ee
diff --git a/.gitignore b/.gitignore
index baaaeb6..0fd74be 100644
--- a/.gitignore
+++ b/.gitignore
@@ -31,6 +31,7 @@
 src/db_bootstrap.h
 src/osmo-hlr
 src/osmo-hlr-db-tool
+src/osmo-euse-demo
 src/gsupclient/gsup-test-client
 
 tests/atconfig