ligo-common.spec: fixed replacement of old name

Co-authored-by: Adam Mercer <adam.mercer@ligo.org>

ligo-common.spec

 %define name ligo-common
 %define version 1.0.3
 %define unmangled_version 1.0.3
-%define release 2
+%define release 3
 
 Summary: Empty LIGO modules
 Name: %{name}
@@ -26,10 +26,11 @@ Empty module placeholder for other LIGO modules
 # -- python2-ligo-common
 
 %package -n python2-%{name}
+Obsoletes: %{name}
 Provides: %{name}
+Conflicts: %{name}
 Summary: %{summary}
 Requires: python
-Obsoletes: ligo-common < 1.0.2-2
 
 %{?python_provide:%python_provide python2-%{name}}