Add profile_id parameter to 'request_certificate'

Add the profile_id parameter to the 'request_certificate' function
and update call sites.

Also remove multiple occurrences of the default profile ID
'caIPAserviceCert'.

Part of: https://fedorahosted.org/freeipa/ticket/57

Reviewed-By: Martin Basti <mbasti@redhat.com>

ipapython/dogtag.py

@@ -47,6 +47,8 @@ INCLUDED_PROFILES = {
     (u'caIPAserviceCert', u'Standard profile for network services', True),
     }
 
+DEFAULT_PROFILE = u'caIPAserviceCert'
+
 class Dogtag10Constants(object):
     DOGTAG_VERSION = 10
     UNSECURE_PORT = 8080