info.c: add modes

Since a provider might require an app to support certain modes (e.g.
FI_LOCAL_MR), info.c should specify all modes in its getinfo() query.  This also helps to see all modes supported/suggested by a provider.

Signed-off-by: Reese Faucette <rfaucett@cisco.com>
How about we just set mode = ~0, so we're covered in the future?