Fix to close fd for pgpool_status.

Per coverity 1230543.
First checkin for fixing [pgpool-hackers: 592]. pool_error and elog
This commit modernise the debug and log reporting mechanism and replace
all the function calls of pool_log() and pool_debug() with elog API's ereport().
As part of the effort log and debug message strings are also enhanced
to make the report more consistent and informative.
Next step on resolving this issue ([pgpool-hackers: 592]) is to remove pool_error().
This is little more trickier because of long jump in elog(ERROR,..) which alters the code flow.
Fix coverity issue 1111480 Copy into fixed size buffer
replacing strcpy() with much safer and recomended call strlcpy()