replica install: track the RA agent certificate again
    
    During the rebase of commit 822e1bc82af3a6c1556546c4fbe96eeafad45762 on top
    of commit 808b1436b4158cb6f926ac2b5bd0979df6ea7e9f, the call to track the
    RA agent certificate with certmonger was accidentally removed from
    ipa-replica-install.
    
    Put the call back so that the certificate is tracked after replica install.
    
    https://fedorahosted.org/freeipa/ticket/6392
    
    Reviewed-By: Tomas Krizek <tkrizek@redhat.com>