__timezone and __tzname pages have empty <refname> tag

[Jeff Johnson]

On __timezone and __tzname pages, one can currently see the following:

Name
 -- external variable containing timezone

(http://refspecs.linux-foundation.org/LSB_4.0.0/LSB-Core-generic/LSB-Core-generic/baselib---timezone.html,
http://refspecs.linux-foundation.org/LSB_4.0.0/LSB-Core-generic/LSB-Core-generic/baselib---tzname.html)

Other pages normally have symbol name before '--', e.g.:

Name
__daylight -- external daylight savings time flag

This comes from the fact that __timezone.sgml and __tzname.sgml have empty
<refname> tag which should contain symbol name.