Ticket #48919 - Compiler warnings while building 389-ds-base on RHEL7
    
    Description: Fixing additional covscan errors.
    1. RESOURCE_LEAK
       ldap/servers/slapd/agtmmap.c
       agt_mopen_stats - leaked_handle: Handle variable "fd" going out of scope leaks the handle.
    2. CHECKED_RETURN
       ldap/servers/slapd/back-ldbm/cache.c
       entrycache_return - check_return: Calling "remove_hash" without checking return value
    3. NULL_RETURNS
       ldap/systools/idsktune.c
       linux_check_cpu_features - dereference: Dereferencing a pointer that might be null "cpuinfo" when calling "fclose".
    4. UNINIT
       ldap/servers/slapd/detach.c
       detach - uninit_use: Using uninitialized value "rc".
    
    https://fedorahosted.org/389/ticket/48919