remove support for EL<6

Change-Id: Ic8ee01c69128f7bc4ec90a1d16a67b016a342b11

contrib/redhat/collectd.spec

@@ -227,26 +227,6 @@
 # not sure why this one's failing
 %define with_write_stackdriver 0%{!?_without_write_stackdriver:0}
 
-# Plugins not buildable on RHEL < 6
-%if 0%{?rhel} && 0%{?rhel} < 6
-%define with_ceph 0
-%define with_curl_json 0
-%define with_log_logstash 0
-%define with_dns 0
-%define with_ethstat 0
-%define with_gmond 0
-%define with_iptables 0
-%define with_ipvs 0
-%define with_modbus 0
-%define with_netlink 0
-%define with_redis 0
-%define with_smart 0
-%define with_turbostat 0
-%define with_write_prometheus 0
-%define with_write_redis 0
-%define with_write_riemann 0
-%endif
-
 # Plugins not buildable on RHEL < 7
 %if 0%{?rhel} && 0%{?rhel} < 7
 %define with_connectivity 0
@@ -756,11 +736,7 @@ Summary:	Perl plugin for collectd
 Group:		System Environment/Daemons
 Requires:	%{name}%{?_isa} = %{version}-%{release}
 Requires:	perl(:MODULE_COMPAT_%(eval "`%{__perl} -V:version`"; echo $version))
-	%if 0%{?rhel} && 0%{?rhel} < 6
-BuildRequires:	perl
-	%else
 BuildRequires:	perl-ExtUtils-Embed
-	%endif
 %description perl
 The Perl plugin embeds a Perl interpreter into collectd and exposes the
 application programming interface (API) to Perl-scripts.
@@ -824,21 +800,10 @@ Monitors process starts/stops via netlink library.
 Summary:	Python plugin for collectd
 Group:		System Environment/Daemons
 Requires:	%{name}%{?_isa} = %{version}-%{release}
-%if 0%{?rhel}
-%if 0%{?rhel} == 8
+%if 0%{?rhel} && 0%{?rhel} >= 8
 BuildRequires: python3-devel
-%endif
-%if 0%{?rhel} == 7
-BuildRequires: python2-devel
-%endif
-%if 0%{?rhel} == 6
-BuildRequires: python2-devel
-%endif
-%if 0%{?rhel} <= 5
-BuildRequires: python-devel
-%endif
 %else
-BuildRequires: python-devel
+BuildRequires: python2-devel
 %endif
 %description python
 The Python plugin embeds a Python interpreter into collectd and exposes the
@@ -1717,12 +1682,7 @@ Collectd utilities
 %endif
 
 %if %{with_python}
-	%if 0%{?rhel} && 0%{?rhel} < 6
-%define _with_python --enable-python --with-python=%{_bindir}/python2.6
-%define _python_config PYTHON_CONFIG="%{_bindir}/python2.6-config"
-	%else
 %define _with_python --enable-python
-	%endif
 %else
 %define _with_python --disable-python
 %endif