Log Message:
Split out deinstall portions of INSTALL scripts into DEINSTALL scripts.
This avoids the need for a confusing line of the form:

	DEINSTALL_TEMPLATE+=	path/to/INSTALL

in the package Makefile, and actually removes the need to specify it
altogether since by convention, the existence of the DEINSTALL script
is enough to add it to DEINSTALL_TEMPLATE.