add description of -no_ecdhe option to s_server man page

While the -help message references this option, the man page
doesn't mention the -no_ecdhe option.
This patch fixes this omission.
add description of -attime to man page

the verify app man page didn't describe the usage of attime option
even though it was listed as a valid option in the -help message.

This patch fixes this omission.