www/nginx-devel: update NGINX JavaScript module to 0.7.3

Bump PORTREVISION.

<ChangeLog>

Core:

*) Feature: added support of module resolution callback.

This feature allows a host environment to control
how imported modules are loaded.

*) Bugfix: fixed backtraces while traversing imported user

modules.

*) Bugfix: fixed Array.prototype.concat() when "this" is a slow

array.

*) Bugfix: fixed frame allocation from an awaited frame.

*) Bugfix: fixed allocation of large array literals.

*) Bugfix: fixed interpreter when "toString" conversion fails.

</ChangeLog>