Install systemd services with autotools

Change-Id: I3a87d5ad4cb43efdcfc25828144f825f4d3b1594
diff --git a/contrib/Makefile.am b/contrib/Makefile.am
new file mode 100644
index 0000000..3439c97
--- /dev/null
+++ b/contrib/Makefile.am
@@ -0,0 +1 @@
+SUBDIRS = systemd
diff --git a/contrib/systemd/Makefile.am b/contrib/systemd/Makefile.am
new file mode 100644
index 0000000..8648172
--- /dev/null
+++ b/contrib/systemd/Makefile.am
@@ -0,0 +1,5 @@
+if HAVE_SYSTEMD
+EXTRA_DIST = osmo-msc.service
+systemdsystemunit_DATA = \
+  osmo-msc.service
+endif