minor changes in psql's \encoding command

Hi all,

While developing one of our applicatins,
we found that psql's meta command \encoding
return different result to what
"SHOW CLIENT_ENCODING" command return.
And it make us somewhat difficult to determine
our problem. After take a look at source of psql
and libpq, I found that the \encoding command
only use the encoding setting while connection was made.
don't know why, but a few changes make \encoding command
synchronized with "SHOW CLIENT_ENCODING" &
"SET CLIENT_ENCODING TO 'something'"

please apply it if it's useful.

regards laser