Ticket 49386 - Memberof should be ignore MODRDN when the pre/post entry are identical
    
    Bug Description:
    	If a modrdn command renames an entry in itself it is inexpensive for the
    	core server but can be expensive for memberof.
    	member will update all entries referring (memberof value) the target entry.
    	The updates will delete and add back the target entry DN.
    
    Fix Description:
    	In the early step of memberof modrdn callback, checks if pre_sdn and post_sdn
    	are identical.
    	If they are it skips the update
    
    https://pagure.io/389-ds-base/issue/49386
    
    Reviewed by: Mark Reynolds
    
    Platforms tested: F23
    
    Flag Day: no
    
    Doc impact: no
    
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