json parser flags

During profiling deserialization of json was on 5th place in terms of
time taken. I found 2 flags which could help us reduce parsing time.
When I tested the changes locally there was no big difference but I
wonder how it would like in scale.


Change-Id: If4b1338aae009d7d997165d3d2d33559f8e21cf2
Signed-off-by: pkliczewski <piotr.kliczewski@gmail.com>