updgrade documentation - copy plugins directory

[dan]

Following the UPGRADING instructions strictly you could not install the plugins directory.

Add the new instruction 2 and renumber.

--- UPGRADING   (revision 2522)
+++ UPGRADING   (working copy)
@ -14,16 +14,17 @@
    - ./program/
    - ./installer/
    - ./skins/default/
-2. Run ./bin/update.sh from the commandline OR
+2. Copy the ./plugins directory to your new installation.
+3. Run ./bin/update.sh from the commandline OR
    open http://url-to-roundcube/installer/ in a browser. To enable
    the latter one, you have to temporary set 'enable_installer' to true
    in your local config/main.inc.php file.
-3. Let the update script/installer check your configuration and
+4. Let the update script/installer check your configuration and
    update your config files as suggested by the updater.
-4. If suggested by the update script, run all commands in
+5. If suggested by the update script, run all commands in
    ./SQL/[yourdbtype].update.sql that are superscribed with the
    currently installed version number.
-5. Make sure 'enable_installer' is set to false again.
+6. Make sure 'enable_installer' is set to false again.

[alec]

Fixed in [fc110250].