Remove obsolete Group tag

References: https://fedoraproject.org/wiki/Changes/Remove_Group_Tag

iperf3.spec

@@ -3,7 +3,6 @@ Version:        3.6
 Release:        3%{?dist}
 Summary:        Measurement tool for TCP/UDP bandwidth performance
 
-Group:          Applications/Internet
 License:        BSD
 URL:            http://github.com/esnet/iperf
 Source0:        http://downloads.es.net/pub/iperf/iperf-%{version}.tar.gz
@@ -17,7 +16,6 @@ jitter, data-gram loss.
 
 %package        devel
 Summary:        Development files for %{name}
-Group:          Development/Libraries
 Requires:       %{name}%{?_isa} = %{version}-%{release}
 
 %description    devel