jvpp: stop plugin intialization on first mismatch

Java bindings use get_message_id from jvpp-common
to detect if messages known at compile time
are avaliable at runtime.

In case of missing entry, Java exception is propagated
via JNI using (*env)->ThrowNew.

But this function does not end code execution so,
in order to prevent unexpected behaviour
(e.g. calling vl_msg_api_set_handlers with id == 0),
get_message_id caller should do it manually.

Change-Id: I2edb5013fd3658dcdd77a867b5cdf62e559ee071
Signed-off-by: Marek Gradzki <mgradzki@cisco.com>