Add DNS Setup Prompt to Install

Currently the only way to setup integrated DNS is by passing --setup-dns
to ipa-server-install. This patch modifies install so that if
--setup-dns is not passed, the user is asked if they want to configure
integrated dns.

http://fedorahosted.org/freeipa/ticket/2575

install/tools/ipa-server-install

@@ -750,6 +750,11 @@ def main():
     admin_password = ""
     reverse_zone = None
 
+    if not options.setup_dns and not options.unattended:
+        if ipautil.user_input("Do you want to configure integrated DNS (BIND)?", False):
+            options.setup_dns = True
+        print ""
+
     # check bind packages are installed
     if options.setup_dns:
         if not bindinstance.check_inst(options.unattended):