PDB-342 Fix order precedence issue with boolean logic for use_our_jdk test

The use_our_jdk variable was being set to true when it should have been false.
This was because the assignment operator = was taking priority over the 'and'
operator. Wrapping the entire 'and' clause in brackets seems to have solved
this.

Signed-off-by: Ken Barber <ken@bob.sh>