[DOC] fix release number in pdf title
[DOC] fix release number in pdf title

When downloading pdf from readthedocs, title has old release version.
https://readthedocs.org/projects/shinken/downloads/pdf/latest/

dfranco/shinken,claneys/shinken,peeyush-tm/shinken,Simage/shinken,KerkhoffTechnologies/shinken,rednach/krill,kaji-project/shinken,staute/shinken_deb,savoirfairelinux/shinken,staute/shinken_deb,gst/alignak,rednach/krill,geektophe/shinken,fpeyre/shinken,Simage/shinken,tal-nino/shinken,dfranco/shinken,mohierf/shinken,kaji-project/shinken,lets-software/shinken,rledisez/shinken,lets-software/shinken,lets-software/shinken,titilambert/alignak,rednach/krill,tal-nino/shinken,rednach/krill,fpeyre/shinken,geektophe/shinken,fpeyre/shinken,lets-software/shinken,ddurieux/alignak,lets-software/shinken,ddurieux/alignak,rledisez/shinken,KerkhoffTechnologies/shinken,mohierf/shinken,claneys/shinken,Simage/shinken,staute/shinken_deb,Aimage/shinken,Simage/shinken,staute/shinken_deb,naparuba/shinken,ddurieux/alignak,mohierf/shinken,rednach/krill,Aimage/shinken,savoirfairelinux/shinken,dfranco/shinken,tal-nino/shinken,claneys/shinken,staute/shinken_package,titilambert/alignak,peeyush-tm/shinken,savoirfairelinux/shinken,titilambert/alignak,gst/alignak,gst/alignak,KerkhoffTechnologies/shinken,Alignak-monitoring/alignak,kaji-project/shinken,savoirfairelinux/shinken,fpeyre/shinken,mohierf/shinken,naparuba/shinken,geektophe/shinken,mohierf/shinken,staute/shinken_deb,ddurieux/alignak,rledisez/shinken,claneys/shinken,peeyush-tm/shinken,geektophe/shinken,titilambert/alignak,KerkhoffTechnologies/shinken,rledisez/shinken,staute/shinken_deb,kaji-project/shinken,gst/alignak,dfranco/shinken,savoirfairelinux/shinken,dfranco/shinken,ddurieux/alignak,geektophe/shinken,mohierf/shinken,kaji-project/shinken,rledisez/shinken,naparuba/shinken,Aimage/shinken,naparuba/shinken,Aimage/shinken,staute/shinken_package,peeyush-tm/shinken,KerkhoffTechnologies/shinken,staute/shinken_package,Simage/shinken,Simage/shinken,tal-nino/shinken,KerkhoffTechnologies/shinken,claneys/shinken,tal-nino/shinken,kaji-project/shinken,savoirfairelinux/shinken,tal-nino/shinken,Aimage/shinken,claneys/shinken,rledisez/shinken,kaji-project/shinken,staute/shinken_package,naparuba/shinken,geektophe/shinken,staute/shinken_package,lets-software/shinken,staute/shinken_package,rednach/krill,dfranco/shinken,peeyush-tm/shinken,naparuba/shinken,Aimage/shinken,Alignak-monitoring/alignak,ddurieux/alignak,fpeyre/shinken,peeyush-tm/shinken,fpeyre/shinken