[Drbd-dev] fix missing directory creation in "make install"

[Florian Haas]

Lars/Phil,

please consider the following patch, which ensures that "make install"
creates DRBD_RUN_DIR. Issue highlighted by Eric Robinson, see:

http://lists.linux-ha.org/pipermail/linux-ha/2011-November/044198.html

The fix to DRBD_LIB_DIR is merely cosmetic I guess; I strongly doubt
anyone ever overrides the PACKAGE_TARNAME. But it doesn't hurt not
to hard-code "drbd" here.

The patch is in my repo at git://github.com/fghaas/drbd-8.4.git --
feel free to pull from there.

Thanks,
Florian