(ITS#8303) An Asynchronous meta back-end - some fixes

[nivanova@symas.com]

Some new bug fixes for asyncmeta:
1.Fix for a crash during an add operation
ftp://ftp.openldap.org/incoming/Nadezhda-Ivanova-160607_01.patch
2. Asyncmeta ignored ors_tlimit if operation timeout was configured
ftp://ftp.openldap.org/incoming/Nadezhda-Ivanova-160607_02.patch
3. Fixed uninitialized control value during copy of operation, which 
caused occasional crashes when controls without values are used.
ftp://ftp.openldap.org/incoming/Nadezhda-Ivanova-160607_03.patch
4. Fixed a missing result message if onerr=continue and the last result 
is an error.
ftp://ftp.openldap.org/incoming/Nadezhda-Ivanova-160607_04.patch
5. Fixed incorrect copy of the entry of an add operation, which resulted 
in memory leaks.
ftp://ftp.openldap.org/incoming/Nadezhda-Ivanova-160607_05.patch

Best Regards,
Nadezhda Ivanova