Improvement of log messages in pg_basebackup

Hi,

> fprintf(stderr, _("%s: could not identify system: %s\n"),
> progname, PQerrorMessage(conn));

Since PQerrorMessage() result includes a trailing newline, the above
log message in pg_basebackup doesn't need to include a trailing \n.
Attached patch gets rid of that \n.

> res = PQgetResult(conn);
> if (PQresultStatus(res) != PGRES_TUPLES_OK)
> {
> fprintf(stderr, _("%s: could not get WAL end position from server\n"),
> progname);

ISTM it's worth including PQerrorMessage() result in the above log
message, to diagnose the cause of error. Attached patch does that.

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center