Remove obsolete Group tag

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

glog.spec

@@ -2,7 +2,6 @@ Name:           glog
 Version:        0.3.5
 Release:        6%{?dist}
 Summary:        A C++ application logging library
-Group:          System Environment/Libraries
 License:        BSD
 URL:            https://github.com/google/glog
 Source0:        https://github.com/google/%{name}/archive/v%{version}/%{name}-%{version}.tar.gz
@@ -21,7 +20,6 @@ streams and various helper macros.
 
 %package        devel
 Summary:        Development files for %{name}
-Group:          Development/Libraries
 Requires:       %{name} = %{version}-%{release}
 
 %description    devel