virtcli: Add python3 version check

Assume 3.4 is needed, we may support earlier but I doubt anyone
is going to get all the deps in place on a distro that old

setup.py

@@ -20,15 +20,15 @@ import distutils.dist
 import distutils.log
 import distutils.sysconfig
 
+if sys.version_info.major < 3:
+    print("virt-manager is python3 only. Run this as ./setup.py")
+    sys.exit(1)
+
 from virtcli import CLIConfig
 
 sysprefix = distutils.sysconfig.get_config_var("prefix")
 
 
-if sys.version_info.major < 3:
-    print("virt-manager is python3 only. Run this as ./setup.py")
-    sys.exit(1)
-
 # pylint: disable=attribute-defined-outside-init
 
 _desktop_files = [

virtcli/cliconfig.py

@@ -9,9 +9,15 @@
 Configuration variables that can be set at build time
 """
 
-import configparser
 import os
+import sys
 
+if sys.version_info.major != 3 or sys.version_info.minor < 4:
+    print("python 3.4 or later is required, your's is %s" %
+            sys.version_info)
+    sys.exit(1)
+
+import configparser
 
 _cfg = configparser.ConfigParser()
 _filepath = os.path.abspath(__file__)