update rpmbuild dependencies re Py3 rockstor#17

## Includes
- remove python3-distro - sourced from venv now.
- provisional Python 3.8 in Tumbleweed.

rockstor.spec

@@ -35,7 +35,7 @@ Prefix: /opt
 # which is in-turn exported as a shell variable of RPM_BUILD_ROOT
 BuildRoot: /var/tmp/%{name}-%{version}-%{release}-build
 
-# BuildRequires: python2
+BuildRequires: python3
 BuildRequires: systemd
 BuildRequires: systemd-rpm-macros
 # For when we update to current poetry for our build (Python 3 only):
@@ -86,7 +86,6 @@ Requires: nut-drivers-net
 Requires: net-snmp
 Requires: docker
 Requires: cryptsetup
-Requires: python3-distro
 Requires: dnf-yum
 Requires: dnf-plugins-core
 Requires: python3-python-dateutil
@@ -115,9 +114,8 @@ Requires: make
 # Version unreliable as changes over time !
 %if 0%{?suse_version} >= 1599
 # Nearest Python 3 in TW to our interim Py3.6 target is 3.8:
-# So re remark out to test Poetry installing 3.6 to venv.
-# Requires: python38
-# Requires: python38-devel
+Requires: python38
+Requires: python38-devel
 Requires: NetworkManager
 Requires: nginx
 Requires: btrfsprogs
@@ -149,7 +147,6 @@ Requires: nut-drivers-net
 Requires: net-snmp
 Requires: docker
 Requires: cryptsetup
-# Requires: python3-distro
 Requires: dnf-yum
 Requires: dnf-plugins-core
 Requires: python3-python-dateutil