rpm spec: remove %{extra_release} from spec

The %{extra_release} field was previously populated by data from the old
autobuild.sh file but is no longer used.
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

libvirt.spec.in

@@ -214,7 +214,7 @@
 Summary: Library providing a simple virtualization API
 Name: libvirt
 Version: @VERSION@
-Release: 1%{?dist}%{?extra_release}
+Release: 1%{?dist}
 License: LGPLv2+
 URL: https://libvirt.org/
 

mingw-libvirt.spec.in

@@ -35,7 +35,7 @@
 
 Name:           mingw-libvirt
 Version:        @VERSION@
-Release:        1%{?dist}%{?extra_release}
+Release:        1%{?dist}
 Summary:        MinGW Windows libvirt virtualization library
 
 License:        LGPLv2+