Errno 115 returned on successful completion for several system calls

While exercising the new harness for integration tests, I noticed that system calls open(), stat(), mkdir(), getdents(), and rmdir() return errno 115, (EINPROGRESS "Operation now in progress") rather than 0 when the system calls succeed. Note that this list is by no means exhaustive, it just covers the system calls were I detected the wrong behavior. My guess is that we are not resetting errno correctly between system calls.