The only DRBD packages required for recent versions of XCP/Xenserver (version 7+) are
drbd84-utils-9.6.0-1.el7.elrepo.x86_64
drbd84-utils-sysvinit-9.6.0-1.el7.elrepo.x86_64
The install_nosan_deps script will install just these two. No other DRBB packages are needed as the kernel now has DRBD shipped with it.
Can you try uninstalling drbd-xen, drbd-utils, drbd-udev.... and then run the script below again?