fabric: Add mode bits to RX/TX attributes

When an RX/TX context is opened, an application can
specify a subset of the capabilities requested of the
endpoint.  As a result, the provider may be able to
provide relaxed mode bits.

For example, an endpoint that supports both tagged
messages and RMA operations may require FI_CONTEXT
mode bits.  However, a TX context that will only be
used for RMA may not require this mode.  By removing
this mode, an application may see improved performance
when using the RMA TX without needing to allocate
fi_context structures.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
man/fi_errno: Add man page that describes list of errors

Provide a man page that defines possible fabric errors and
their general meaning.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
fabric: Define FI_NOCQ

Now that the CQ was spun off the EQ, define FI_NOCQ,
similar to FI_NOEQ.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
fabric: Define FI_COMPLETION

Rather than using FI_EVENT to indicate that a completion
should be generated for a given operation, allow the user
to specify this using FI_COMPLETION.  FI_COMPLETION is
defined with the same value as FI_EVENT to avoid using
another flag bit and allow either value to be used.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>