db-parser: use additional <value> tags in pdbtool match --debug-pattern

pdbtool match when used with the --debug-pattern option used a low-level
lookup function, that didn't perform all the db-parser actions specified
in the rule. This patch fixes that.

Signed-off-by: Balazs Scheidler <balazs.scheidler@balabit.com>
Merge pull request #301 from balabit/f/pdbtool-match-use-explicit-value-assignments

db-parser: use additional <value> tags in pdbtool match --debug-pattern