Use Dogtag 10 only when it is available

Put the changes from Ade's dogtag 10 patch into namespaced constants in
dogtag.py, which are then referenced in the code.

Make ipaserver.install.CAInstance use the service name specified in the
configuration. Uninstallation, where config is removed before CA uninstall,
also uses the (previously) configured value.

This and Ade's patch address https://fedorahosted.org/freeipa/ticket/2846

ipalib/constants.py

@@ -141,9 +141,11 @@ DEFAULT_CONFIG = (
     ('ca_port', 80),
     ('ca_agent_port', 443),
     ('ca_ee_port', 443),
-    ('ca_install_port', 8080),
-    ('ca_agent_install_port', 8443),
-    ('ca_ee_install_port', 8443),
+    # For the following ports, None means a default specific to the installed
+    # Dogtag version.
+    ('ca_install_port', None),
+    ('ca_agent_install_port', None),
+    ('ca_ee_install_port', None),
 
 
     # Special CLI:
@@ -156,6 +158,7 @@ DEFAULT_CONFIG = (
     ('enable_ra', False),
     ('ra_plugin', 'selfsign'),
     ('wait_for_attr', False),
+    ('dogtag_version', 9),
 
     # Used when verifying that the API hasn't changed. Not for production.
     ('validate_api', False),