Bug 22958: Fix help link on the SMS providers page

Bug 22958: Fix help link on the SMS providers page

The help link on the SMS providers page didn't link to the
according chapter in the manual.

To test:
- Enter Email in SMSSendDriver system preference to
  make the configuration page appear
- Go to Administration > SMS cellular providers
- Click on the help link
- Verify it leads to the manual start page
- Apply patch
- Repeat and verify the link now leads to the correct
  section in the manual

Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>