Fix project & version for Phosphorus

Fix project & version for Phosphorus

OpenDaylight documentation site for Phosphorus currently shows
'transportpce' & 'stable-phosphorus' as the project name & version,
respectively, instead of 'OpenDaylight Documentation' & 'Phosphorus'
as configured in conf.yaml because global variables 'project' and
'version' are overridden while 'intersphinx_mapping' is getting
updated.

Move the for-loop to update 'intersphinx_mapping' inside a function
to prevent the global 'project' & 'version' variables from being
inadvertently updated.

Change-Id: I9a418f29f8d5710c822985bbfe7e7c62743bc46b
Signed-off-by: Sangwook Ha <sangwook.ha@verizon.com>