Remove obsolete Group tag

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

gavl.spec

@@ -3,7 +3,6 @@ Version:        1.4.0
 Release:        13%{?dist}
 Summary:        A library for handling uncompressed audio and video data
 
-Group:          System Environment/Libraries
 License:        GPLv3+
 URL:            http://gmerlin.sourceforge.net/
 Source0:        http://downloads.sourceforge.net/gmerlin/gavl-%{version}.tar.gz
@@ -33,7 +32,6 @@ user options.
 
 %package        devel
 Summary:        Development files for %{name}
-Group:          Development/Libraries
 Requires:       %{name} = %{version}-%{release}
 Requires:       pkgconfig