Bump libsqlfs to latest
Fix include path for building libsqlfs

libsqlfs now detects the presence of SQLCipher and alters the include path accordingly.
Pass '0' to sqlfs_* functions to use the pthread_key_t tracked sqlfs
Change the VFS semantics to be more multi threading friendly.

This is a transitional commit as we lose the meaning of unmount()
and several important error conditions (e.g., bad key), however, it
should be more multi-threads friendly.

Requires latest libsqlfs (bumped)
Use latest sqlfs API when passing key data
Detect incorrect key when mounting an encrypted VFS