Revert "xbps-src: allow to use install-destdir for pkgs already installed."

This reverts commit 4478b5ead3c1a1138728e5d7ea4f4ec3838703ab.

xbps-src/shutils/pkgtarget_funcs.sh.in

@@ -52,11 +52,9 @@ install_pkg()
 	check_installed_pkg "$pkg"
 	if [ $? -eq 1 -o $? -eq 0 ]; then
 		instver="$($XBPS_PKGDB_CMD version $pkgname)"
-		if [ -n "$instver" -a "$install_destdir_target" = "no" ]; then
+		if [ -n "$instver" ]; then
 			echo "=> $pkgname-$instver already installed."
 			return 0
-		elif [ -n "$instver" -a "$install_destdir_target" = "yes" ]; then
-			echo "=> $pkgname-$instver installed, continuing for DESTDIR installation..."
 		fi
 	fi