Rename renamed nsm.el variables and functions back

* doc/emacs/misc.texi (Network Security): Start working on
updating the NSM bits, but it's unclear how much of the new stuff
to document.

* lisp/net/nsm.el: Rename all nsm-tls-check-* functions to
nsm-protocol-check--* to bring them back into line with the
(network-security-protocol-checks): Renamed back again from
`nsm-tls-checks', as this variable is documented and can't just go
1 job for master in 3 minutes and 23 seconds (queued for 3 seconds)
Status Job ID Name Coverage
failed #3102


Name Stage Failure
test-all Test
Makefile:402: recipe for target 'xdisp.o' failed
make[2]: *** [xdisp.o] Error 1
make[2]: Leaving directory '/builds/emacs/emacs/src'
make[1]: *** [src] Error 2
Makefile:424: recipe for target 'src' failed
make[1]: Leaving directory '/builds/emacs/emacs'
Makefile:1117: recipe for target 'bootstrap' failed
make: *** [bootstrap] Error 2
ERROR: Job failed: exit code 1