Prevents ganesha from segfaulting if config item FSAL=<fsalname> is duplicated in configuration file
This patch adds option to the mount.9P helper:

It adds option "cache=" to make it possible to pass "-o cache=mmap" to 9p mount.
This mount option is a requirement for fixed 9p's mmap bug.
The cache=mmap mount option for 9p comes for kernel 3.14

It adds option "context=<some selinux context>" to make it possible to set the default selinux content for a 9p mount point.
nfs_init_svc: properly init memory (svc_params)

Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
lower_my_caps: properly init memory (caphdr)

Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
fsal_types.h: remove unused FSAL_DIGEST_SIZE_HDLV[234] constants

Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
CMake: s/ERROR/FATAL_ERROR/ on gssapi not found

Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
cmake/gitdesc_from_path: posixify script

Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
nfs_init: s/ifdef LINUX/ifdef USE_CAPS/ to include libcap headers

Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>