Description of problem:
rfc1912 states DNS serial won't overflow until the year 4294, which as per the
syntax makes 4294123199 a valid value.

Version-Release number of selected component (if applicable):
ipa-server-2.2.0-4.el6.x86_64

How reproducible:
Always

Steps to Reproduce:
[root@primenova ~]# ipa dnszone-add testzone --serial=4294123199

Actual results:
ipa: ERROR: invalid 'serial': can be at most 2147483647

Expected results:
Zone should be created successfully and at most should be 4294123199.

Additional info:
http://www.ietf.org/rfc/rfc1912.txt