Camera: Reset metadata entry before ZSL query

Reset the metadata entry argument before doing consecutive
queries without checking the query status.
In case the query fails, we could access a value that was
set from a previous successful query.
This can affect the ZSL status flag, frame counting and
eventually cause sequence callbacks to get skipped.

Bug: 179265466
Test: Camera CTS
Change-Id: I4b6834d17235c4845c9b0ff6e465467c5e9be8a0