java-utils-2.eclass: Write package.env unconditionally

java-utils-2.eclass: Write package.env unconditionally

Fixes dev-db/sqldeveloper-4.1.3.20.78-r1. This is a case where all the
jars are installed without dojar and none of the dependencies are
mandatory. Although our regular launcher scripts aren't used, gjl is
still invoked to determine the appropriate JVM so package.env is
therefore necessary. The conditions didn't make much sense anyway as
package.env is only written off the back of functions that satisfy
them anyway. sqldeveloper has to call java-pkg_do_write_ manually to
force package.env to be written.