Ticket 47738 - use PL_strcasestr instead of strcasestr
    
    Bug Description:  The use of strcasestr results in unresolved symbols for
                      libacl-plugin.so on build on Solaris
    
    Fix Description:  Use PR_strcasestr
    
    Original patch submitted by: cgrzemba(Thanks!)
    
    https://fedorahosted.org/389/ticket/47738
    
    Reviewed by: mreynolds
    
    (cherry picked from commit 67177a2108ebf04094be003662f8091ecde5706b)