Update feedparser requires

In Fedora python2-feedparser should be used in Requires but there
is only python-feedparser in EPEL. Let's use conditional then.

https://src.fedoraproject.org/rpms/did/pull-request/3
https://bugzilla.redhat.com/show_bug.cgi?id=1663178

did.spec

@@ -13,7 +13,7 @@ BuildRequires: git
 BuildRequires: python2-devel
 Requires: python2-requests-gssapi
 Requires: python2-nitrate python2-dateutil python2-bugzilla
-Requires: python-feedparser
+Requires: python%{?fedora:2}-feedparser
 
 %description
 Comfortably gather status report data (e.g. list of committed