[dist] Add a RPM provides for obs-devel

Solves rpmlint complain:
"
obs-server.noarch: W: obsolete-not-provided obs-devel
If a package is obsoleted by a compatible replacement, the obsoleted package
should also be provided in order to not cause unnecessary dependency breakage.
If the obsoleting package is not a compatible replacement for the old one,
leave out the Provides.
"

dist/obs-server.spec

@@ -106,6 +106,7 @@ Requires:       /usr/bin/createrepo
 Recommends:     cron logrotate
 
 Obsoletes:      obs-devel
+Provides:       obs-devel
 
 BuildRequires:  xz