Support RPM building via contrib/osmo-e1-recorder.spec.in

Change-Id: I1851b5c2a68ec9559e42c9da3f04d43c0fc7cdfe
diff --git a/Makefile.am b/Makefile.am
index 24f0b24..d8c83a4 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -15,7 +15,7 @@
 	$(NULL)
 
 BUILT_SOURCES = $(top_srcdir)/.version
-EXTRA_DIST = git-version-gen osmoappdesc.py .version
+EXTRA_DIST = git-version-gen osmoappdesc.py .version contrib/osmo-e1-recorder.spec.in
 
 AM_DISTCHECK_CONFIGURE_FLAGS = \
 	--with-systemdsystemunitdir=$$dc_install_base/$(systemdsystemunitdir)