Remove duplicated doc jobs

jjb doc are executed vs all branches and all projects.
At the time of writing, all branches can be verified in the
same way (Istanbul is the last stable release). In a longer
run we may have to switch to a jjb per branch.

Issue-ID: DOC-782
Change-Id: I12882630586f5c3125474c7a9a42cc204de11700
Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
1 file changed