Add manual Provides for libvarnishapi.so.1.

find-provides did not pick up on libvarnishapi.so.1 for varnish-libs
automatically, and find-requires for the main package did. This meant
that package pair was uninstallable.

I don't quite know why this is happening, so I'm working around it
with a hardcoded Provides for now. This is on the critical path for
4.0 release.

redhat/varnish.spec

@@ -49,6 +49,7 @@ available on the following web site: http://www.varnish-cache.org/
 Summary: Libraries for %{name}
 Group: System Environment/Libraries
 BuildRequires: ncurses-devel
+Provides: libvarnishapi.so.1
 #Obsoletes: libvarnish1
 
 %description libs