dynamic debug: line queries failing due to uninitialized local variable

Settings of the form, 'line x module y +p', can fail arbitrarily due to an
uninitialized local variable. With this patch results are consistent, as
expected.

Signed-off-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>