Fix pg_dump support for pre-8.2 versions

Unify indnkeys/indnatts/indnkeyatts usage  for all version of query to get
index information, remove indnkeys column  from query as unused.

Author: Marina Polyakova
Noticed by: Peter Eisentraut

Author: feodor

src/bin/pg_dump/pg_dump.c

@@ -6786,7 +6786,6 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 							  "pg_catalog.pg_get_indexdef(i.indexrelid) AS indexdef, "
 							  "i.indnkeyatts AS indnkeyatts, "
 							  "i.indnatts AS indnatts, "
-							  "t.relnatts AS indnkeys, "
 							  "i.indkey, i.indisclustered, "
 							  "i.indisreplident, t.relpages, "
 							  "c.contype, c.conname, "
@@ -6824,7 +6823,6 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 							  "pg_catalog.pg_get_indexdef(i.indexrelid) AS indexdef, "
 							  "i.indnatts AS indnkeyatts, "
 							  "i.indnatts AS indnatts, "
-							  "t.relnatts AS indnkeys, "
 							  "i.indkey, i.indisclustered, "
 							  "i.indisreplident, t.relpages, "
 							  "c.contype, c.conname, "
@@ -6858,7 +6856,6 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 							  "pg_catalog.pg_get_indexdef(i.indexrelid) AS indexdef, "
 							  "i.indnatts AS indnkeyatts, "
 							  "i.indnatts AS indnatts, "
-							  "t.relnatts AS indnkeys, "
 							  "i.indkey, i.indisclustered, "
 							  "false AS indisreplident, t.relpages, "
 							  "c.contype, c.conname, "
@@ -6888,7 +6885,6 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 							  "pg_catalog.pg_get_indexdef(i.indexrelid) AS indexdef, "
 							  "i.indnatts AS indnkeyatts, "
 							  "i.indnatts AS indnatts, "
-							  "t.relnatts AS indnkeys, "
 							  "i.indkey, i.indisclustered, "
 							  "false AS indisreplident, t.relpages, "
 							  "c.contype, c.conname, "
@@ -6919,7 +6915,8 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
 							  "t.relname AS indexname, "
 							  "0 AS parentidx, "
 							  "pg_catalog.pg_get_indexdef(i.indexrelid) AS indexdef, "
-							  "t.relnatts AS indnkeys, "
+							  "t.relnatts AS indnkeyatts, "
+							  "t.relnatts AS indnatts, "
 							  "i.indkey, i.indisclustered, "
 							  "false AS indisreplident, t.relpages, "
 							  "c.contype, c.conname, "