Fix wrong error assumption when converting "0.0" to double

Fix wrong error assumption when converting "0.0" to double

The function qstrtod calls strtod without first resetting the errno
but verifying it nonetheless. This could lead to situations where
the errno was already set to ERANGE and hence it would mistakenly
assume the conversion could not be done right.

Merge-request: 2507
Reviewed-by: Harald Fernengel <harald.fernengel@nokia.com>