Edgefs: fixes unhandled type assertions
Edgefs: fixes unhandled type assertions

unhandled type assertions can lead to runtime panic. using
the boolean 'ok' flag to handle failure to assert type.

Issue: #4566
Signed-off-by: Umanga Chapagain <078ce6f6b416ac444a5caae3922c36dd4ff12c22@gmail.com>

rook/nfs,rook/rook,rook/rook,rook/rook,rook/rook,rook/nfs,rook/rook,rook/nfs