Ticket 49639 - Crash when failing to read from SASL conn
Description: This is a regression from ticket 49618, a return code
integer was reset to a unsigned int, when it needed to
remain signed. This allowed an error condition to go
unchecked, which leads to a crash caused by a large
realloc attempt from the overflowed integer result code.
https://pagure.io/389-ds-base/issue/49639
Reviewed by: mreynolds(one line commit rule)