* libamu/mount_fs.c (compute_nfs_attrcache_flags): use new

* libamu/mount_fs.c (compute_nfs_attrcache_flags): use new
hasmntvalerr() function to set attribute cache values only if they
were set (regardless whether they were set to zero or a non-zero
value).  Before, we were unable to distinguish between an error to
parse an option, and a user who actually wanted to set an
attribute-cache value to 0.  This now fixes an important
performance bug that Amd was turning off the attribute caches even
for regular (non-automounter) NFS mounts.

* libamu/mtab.c (hasmntvalerr): new function to set the value of
an option into an integer, but ONLY if that options was set and
parsed correctly.  This function returns 1 on error, 0 on success
(instead of always setting the option value to 0).
(hasmntval): wrapper function around hasmntvalerr, which maintains
backwards compatibility (always sets option value to 0, even on
error to parse the option).

* amd/nfs_subr.c (fh_to_mp3): use long int printf format for
fhh_pid.