tentative fix for issue #1026 - Enhanced1

Issue reported by ostrosablin (and mentioned previously but I still
I haven't remembered where):  loading a roguesymset removes any utf8
data that has been set up for primary symset.  The curses interface
explicitly initializes roguesymset to the default set and if config
file has specified OPTIONS=symset:Enhanced1 (or some other uft8 set
if someone adds such), that stays the active set but no longer gets
rendered with the intended symbols.

I have no idea whether having symset and roguesymset both use uft8
with different symbols and/or colors works at all and if so whether
it will still work after this revision, but this prevents loading one
set with non-utf8 while the other still uses utf8 from clearing out
the cached utf8 data.

Closes #1026

doc/fixes3-7-0.txt

@@ -1668,6 +1668,8 @@ curses: with window borders on and align_status:left, restoring brought up a
 curses: after changing curses_mark_synch() to do something, making a menu
 	selection by entering a count that uses more than 1 digit caused the
 	menu to vanish
+curses: setting up default roguesymset at startup clobbered primary symset if
+	config file picked Enhanced1 for primary (core bug exposed by curses)
 Qt: at Xp levels above 20 with 'showexp' On, the combined status field
 	"Level:NN/nnnnnnnn" was too big and truncated by a char at each end
 Qt: searching a text window for something that wasn't found and then searching