Introduced python3 change requested by python team

rrdtool.spec

@@ -24,7 +24,7 @@
 Summary: Round Robin Database Tool to store and display time-series data
 Name: rrdtool
 Version: 1.7.0
-Release: 17%{?dist}
+Release: 18%{?dist}
 License: GPLv2+ with exceptions
 Group: Applications/Databases
 URL: http://oss.oetiker.ch/rrdtool/
@@ -118,16 +118,12 @@ Python RRDtool bindings.
 %endif
 
 %if %{with_python3}
-# Make sure the runtime python is newer than the build one;
-# give a default value to handle parsing in cases when python is not present:
-%{!?rrd_python3_version: %global rrd_python3_version %(%{__python3} -c 'import sys; print(sys.version.split(" ")[0])' || echo "3.14")}
-
 %package -n python3-rrdtool
 %{?python_provide:%python_provide python3-rrdtool}
 Summary: Python RRDtool bindings
 Group: Development/Languages
 BuildRequires: python3-devel, python3-setuptools
-Requires: python3 >= %{rrd_python3_version}
+%{?__python3:Requires: %{__python3}}
 Requires: %{name} = %{version}-%{release}
 
 %description -n python3-rrdtool
@@ -469,6 +465,9 @@ LD_LIBRARY_PATH=%{buildroot}%{_libdir} php -n \
 %endif
 
 %changelog
+* Thu Sep 27 2018 Jaroslav Škarvada <jskarvad@redhat.com> - 1.7.0-18
+- Introduced python3 change requested by python team
+
 * Sat Jul 14 2018 Fedora Release Engineering <releng@fedoraproject.org> - 1.7.0-17
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_29_Mass_Rebuild