[mkgmap-dev] Commit r4472: Make sure that getKeystring() doesn't return something like null=way for a rule which cannot be indexed, e.g.

Version mkgmap-r4472 was committed by gerd on Thu, 19 Mar 2020 Make sure that getKeystring() doesn't return something like null=way for a rule which cannot be indexed, e.g. type()=way [0x02] or type()=way & highway!=* {add blabla} http://www.mkgmap.org.uk/websvn/revision.php?repname=mkgmap&rev=4472