Fix mh-redistribute to work with nmh 1.5 and identities (SF#268)

Fix mh-redistribute to work with nmh 1.5 and identities (SF#268)

Co-authored-by: Jeffrey C Honig <jch@honig.net>
* lisp/mh-e/mh-comp.el (mh-redistribute): Add a non-optional
identity parameter.  Use mh-bare-components to generate a draft,
then apply identity-specific settings.  Add more details to the
"Resent" annotation line.
(mh-dist-formfile): New.
(mh-bare-components): Add a formfile argument.
(mh-edit-again, mh-send-sub): Track the change to
mh-bare-components.
* lisp/mh-e/mh-identity.el (mh-select-identity)
(mh-identity-field): New.