The domain name is duplicated in insertGuest() but it's never
freed leading to the following memleak:

 46 bytes in 6 blocks are definitely lost in loss record 795 of 944
    at 0x4C2CF0F: malloc (vg_replace_malloc.c:299)
    by 0x6E6FE79: strdup (in /lib64/libc-2.26.so)
    by 0x10E665: insertGuest (libvirtSnmp.c:160)
    by 0x10EA7D: libvirtSnmpLoadGuests (libvirtSnmp.c:285)
    by 0x10DB01: libvirtGuestTable_container_load (libvirtGuestTable_data_access.c:230)
    by 0x1133E3: _cache_load (libvirtGuestTable_interface.c:1557)
    by 0x5F2955B: _cache_load (in /usr/lib64/libnetsnmpagent.so.30.0.3)
    by 0x5F2A7FF: netsnmp_cache_helper_handler (in /usr/lib64/libnetsnmpagent.so.30.0.3)
    by 0x5F3CE2C: netsnmp_call_next_handler (in /usr/lib64/libnetsnmpagent.so.30.0.3)
    by 0x5F316B6: table_helper_handler (in /usr/lib64/libnetsnmpagent.so.30.0.3)
    by 0x5F3C8E6: netsnmp_call_handlers (in /usr/lib64/libnetsnmpagent.so.30.0.3)
    by 0x5F4A65E: handle_var_requests (in /usr/lib64/libnetsnmpagent.so.30.0.3)

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>