Additionaly this selects different lxml egg, and "disables" lxml building hack.

Conflicts:

	component/lxml-python/buildout.cfg

It has more immunity on libnetworkcache errors.

As slapos.libnetworkcache does not depend on M2Crypto anymore, but on
existence of openssl in PATH drop building of this library and just
tweak slapgrid-sr environment to allow find the openssl in PATH.

http://git.erp5.org/gitweb/slapos.git/commitdiff/2edb5d390f3f8a8fb2ca2deeb355aa1eb6498796

Additionaly use template engine and separate environment definition to own
section.