Improve error message in ipactl
    
    If a hostname configured in /etc/ipa/default.conf is changed and
    is different from the one stored in LDAP in cn=ipa,cn=etc,$SUFFIX
    ipactl gives an unintelligible error.
    
    This patch improves the error message and also offers a list of
    configured master so that the hostname setting in IPA configuration
    can be easily fixed.
    
    https://fedorahosted.org/freeipa/ticket/1558