Remove very-obsolete estimates of shmem usage from postgresql.conf.sample.

runtime.sgml used to contain a table of estimated shared memory consumption
rates for max_connections and some other GUCs.  Commit 390bfc64 removed
that on the well-founded grounds that (a) we weren't maintaining the
entries well and (b) it no longer mattered so much once we got out from
under SysV shmem limits.  But it missed that there were even-more-obsolete
versions of some of those numbers in comments in postgresql.conf.sample.
Remove those too.  Back-patch to 9.3 where the aforesaid commit went in.

src/backend/utils/misc/postgresql.conf.sample

@@ -62,8 +62,6 @@
 					# (change requires restart)
 #port = 5432				# (change requires restart)
 #max_connections = 100			# (change requires restart)
-# Note:  Increasing max_connections costs ~400 bytes of shared memory per
-# connection slot, plus lock space (see max_locks_per_transaction).
 #superuser_reserved_connections = 3	# (change requires restart)
 #unix_socket_directories = '/tmp'	# comma-separated list of directories
 					# (change requires restart)
@@ -119,10 +117,8 @@
 #temp_buffers = 8MB			# min 800kB
 #max_prepared_transactions = 0		# zero disables the feature
 					# (change requires restart)
-# Note:  Increasing max_prepared_transactions costs ~600 bytes of shared memory
-# per transaction slot, plus lock space (see max_locks_per_transaction).
-# It is not advisable to set max_prepared_transactions nonzero unless you
-# actively intend to use prepared transactions.
+# Caution: it is not advisable to set max_prepared_transactions nonzero unless
+# you actively intend to use prepared transactions.
 #work_mem = 4MB				# min 64kB
 #maintenance_work_mem = 64MB		# min 1MB
 #autovacuum_work_mem = -1		# min 1MB, or -1 to use maintenance_work_mem
@@ -559,9 +555,6 @@
 #deadlock_timeout = 1s
 #max_locks_per_transaction = 64		# min 10
 					# (change requires restart)
-# Note:  Each lock table slot uses ~270 bytes of shared memory, and there are
-# max_locks_per_transaction * (max_connections + max_prepared_transactions)
-# lock table slots.
 #max_pred_locks_per_transaction = 64	# min 10
 					# (change requires restart)