Print the actual DB encoding in the unaccent regression test.

This is to help make it more obvious what the problem is, if the
encoding isn't what the test expects.

contrib/unaccent/expected/unaccent.out

 SET client_min_messages = warning;
 \set ECHO none
 RESET client_min_messages;
+-- must have a UTF8 database
+SELECT getdatabaseencoding();
+ getdatabaseencoding 
+---------------------
+ UTF8
+(1 row)
+
 SET client_encoding TO 'KOI8';
 SELECT unaccent('foobar');
  unaccent 

contrib/unaccent/sql/unaccent.sql

@@ -4,6 +4,9 @@ SET client_min_messages = warning;
 \set ECHO all
 RESET client_min_messages;
 
+-- must have a UTF8 database
+SELECT getdatabaseencoding();
+
 SET client_encoding TO 'KOI8';
 
 SELECT unaccent('foobar');