better v=$(<file) fix (re: fe6d090)

If we're adding a check for flag==3 to limit the fix to v=$(<file),
we might as well use the existing check upon returning the FD.

src/cmd/ksh93/sh/io.c

@@ -1266,8 +1266,6 @@ int	sh_redirect(Shell_t *shp,struct ionod *iop, int flag)
 				if(flag==SH_SHOWME)
 					goto traceit;
 				fd=sh_chkopen(fname);
-				if(flag==3)			/* make sure that $(<file) works...	*/
-					fd=sh_iomovefd(fd);	/* ...with stdin/stdout/stderr closed	*/
 			}
 			else if(sh_isoption(SH_RESTRICTED))
 				errormsg(SH_DICT,ERROR_exit(1),e_restricted,fname);
@@ -1447,7 +1445,7 @@ int	sh_redirect(Shell_t *shp,struct ionod *iop, int flag)
 				sh_close(fn);
 			}
 			if(flag==3)
-				return(fd);
+				return(sh_iomovefd(fd));  /* ensure FD > 2 to make $(<file) work with std{in,out,err} closed */
 			if(fd>=0)
 			{
 				if(np)