osd/OSDCap: fix allow_all() check

Only return true for the global "allow all" if the match does not constrain
us at all.  This matches the set_allow_all() method.

Signed-off-by: Sage Weil <sage@inktank.com>
mon/MonCap: add new MonCap implementation

This is a new class with a new grammer.  Implementation is modeled after
OSDCap, and the semantics are based on the old MonCaps, although somewhat
different (though not in too many important ways, I think).

Note that we complete drop auid support; the semantics for that were a
complete mess.

Signed-off-by: Sage Weil <sage@inktank.com>
mon/MonCap: make encodable

Note that we are not backward compatible with the MonCaps struct.  This is
only passed over the wire, so that's okay; we protect this change with a
wire protocol version bump.

Signed-off-by: Sage Weil <sage@inktank.com>
mon: bump wire protocol version

We have changed MonCap encoding and command semantics (which affects
forwarding).  Bump the wire protocol version.

Signed-off-by: Sage Weil <sage@inktank.com>
mon: transition from MonCap -> MonCaps

Convert all monitor users to use the new MonCap class.

Simplify the semantics around auids by essentially dropping any meaningful
permissions enforcement around them.

Signed-off-by: Sage Weil <sage@inktank.com>