pass xmlhttp request object to error callback function
set error information on context

set error information on context when there is an error on
candidate export.
removed white space
add render function for login template
show login link if user is logged out while exporting

this commit will handle the situation where a user is logged in
when he visits the linkedin profile page, then in another
tab/window logs out from recruiterbox account and then exports
the candidate. Which use to show error message, Now login template
is rendered.