Remove restrictive hook node list check

Commit dd7f6776 added a restrictive check for the node lists returned
by BuildHooksEnv, leading to errors with some LUs, one of which was
fixed in commit 0dfa2c22. As it turns out, other LUs have similar
issues, some not easy to fix. This patch disables the restrictive check
until the BuildHooksEnv functions can be split into one part generating
the actual environment and one generating the node lists.

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>