Enable persistent search by default

From IPA version 3.0, the persistent search is a preferred mechanism
to for DNS zone list management. It will be also a requirement for
several bind-dyndb-ldap features, like SOA serial automatic updates
or DNSSEC.

Make this mechanism default in ipa-server-install and ipa-dns-istall.

https://fedorahosted.org/freeipa/ticket/2524

install/tools/ipa-dns-install

@@ -27,7 +27,7 @@ from ipapython import version
 from ipapython import ipautil, sysrestore
 from ipalib import api, errors, util
 from ipapython.config import IPAOptionParser
-from ipalib.constants import DNS_ZONE_REFRESH
+from optparse import OptionGroup, SUPPRESS_HELP
 import krbV
 import ldap
 from ipapython.ipa_log_manager import *
@@ -52,14 +52,16 @@ def parse_options():
     parser.add_option("--zonemgr", action="callback", callback=bindinstance.zonemgr_callback,
                       type="string",
                       help="DNS zone manager e-mail address. Defaults to hostmaster@DOMAIN")
+    # this option name has been deprecated, persistent search has been enabled by default
     parser.add_option("--zone-notif", dest="zone_notif",
-                      action="store_true", default=False,
-                      help="Let name server receive notification when a new zone is added." \
-                           "Zone refresh is turned off when zone notification is enabled")
+                      action="store_true", default=False, help=SUPPRESS_HELP)
+    parser.add_option("--no-persistent-search", dest="persistent_search",
+                      default=True, action="store_false",
+                      help="Do not enable persistent search feature in the name server")
     parser.add_option("--zone-refresh", dest="zone_refresh",
-                      default=DNS_ZONE_REFRESH, type="int",
-                      help="A delay between checks for new DNS zones. Defaults to %d" \
-                              % DNS_ZONE_REFRESH)
+                      default=0, type="int",
+                      help="When set to non-zero the name server will use DNS zone "
+                           "detection based on polling instead of a persistent search")
     parser.add_option("-U", "--unattended", dest="unattended", action="store_true",
                       default=False, help="unattended installation never prompts the user")
 
@@ -77,9 +79,11 @@ def parse_options():
 
     if options.zone_refresh < 0:
         parser.error("negative numbers not allowed for --zone-refresh")
+    elif options.zone_refresh > 0:
+        options.persistent_search = False   # mutually exclusive features
 
-    if options.zone_notif:   # mutually exclusive features
-        options.zone_refresh = 0
+    if options.zone_notif:
+        print >>sys.stderr, "WARNING: --zone-notif option is deprecated and has no effect"
 
     return safe_options, options
 
@@ -220,7 +224,7 @@ def main():
     bind.setup(api.env.host, ip_address, api.env.realm, api.env.domain,
                dns_forwarders, conf_ntp, reverse_zone, zonemgr=options.zonemgr,
                zone_refresh=options.zone_refresh,
-               zone_notif=options.zone_notif)
+               persistent_search=options.persistent_search)
     bind.create_instance()
 
     # Restart http instance to make sure that python-dns has the right resolver