spec: Remove unneeded Group

Installing ovirt-imageio display this warning:

    2020-04-27T13:16:14Z INFO warning: group Development/Debug does not exist - using root

Remove Group, it is not needed.

Change-Id: I36ecf9ff257dcc0afca7450c30f7115adbe1cd31
Signed-off-by: Nir Soffer <nsoffer@redhat.com>

daemon/ovirt-imageio.spec.in

@@ -9,7 +9,6 @@ Version:   @PACKAGE_VERSION@
 Release:   0@RELEASE_SUFFIX@%{?dist}
 Summary:   oVirt imageio
 
-Group:     Development/Libraries
 License:   GPLv2+
 Url:       https://gerrit.ovirt.org/ovirt-imageio
 Source0:   http://resources.ovirt.org/pub/ovirt-master-snapshot/src/%{name}/%{name}-%{version}.tar.gz