Fix $(...) construction.  Noted and patched by Larry Doolittle
<ldoolitt@recycle.lbl.gov>.  I'm just a patch whore.  :)
diff --git a/hush.c b/hush.c
index ed49798..c55d86f 100644
--- a/hush.c
+++ b/hush.c
@@ -1950,6 +1950,7 @@
 			lookup_param(dest, ctx, &alt);
 			break;
 		case '(':
+			b_getch(input);
 			process_command_subs(dest, ctx, input, ')');
 			break;
 		case '*':