Specify sphinx version (fixes #3275)

The latest version of sphinx installed by easy_install is incompatible with our user guide. This change specifies sphinx version 1.2.3, the required one.
Signed-off-by:James L Parry <jim_parry@bcit.ca>
Revert "Specify sphinx version (fixes #3275)"

This reverts commit 4ac399216f0c745134830149cb17dd5423243dd1.
Specify sphinx version (fixes #3275)

The latest version of sphinx installed by easy_install is incompatible with our user guide. This change specifies sphinx version 1.2.3, the required one.
Signed-off-by:James L Parry <jim_parry@bcit.ca>