Incorporate _osrf_app_request_resend into osrf_app_session_request_resend(),

Incorporate _osrf_app_request_resend into osrf_app_session_request_resend(),
which had been its only caller.  The code is trivial enough that it will be
simple to break out again if necessary.  Meanwhile having it all in a single
function makes it more readable.

Free the hash table of requests correctly; i.e. all of each linked list, not
just the first node.

Various additions and refinements to comments; occasional tweaks to white space.

M    include/opensrf/osrf_app_session.h
M    src/libopensrf/osrf_app_session.c

git-svn-id: svn://svn.open-ils.org/OpenSRF/trunk@1882 9efc2488-bf62-4759-914b-345cdb29e865