references to `africa' file for zone naming and abbrev. conve ntions.

[Olson, Arthur David]

	> A minor nit, but when the zone naming and abbreviation
conventions
	> were moved from tzdata/africa to tzcode/Theory cooresponding
cross
	> references in the comments (See the `africa' file for time
zone naming
	> and abbreviation conventions) comments in other data files
were not
	> updated.

Thanks for the catch. I've simply eliminated the cross references to
avoid
dangling pointers to a "Theory" file that some vendors may not
distribute.
Folks can expect to see the deletions (or rather not see them)
the next time a tzdata archive goes out.

				--ado