integration fix: attempt to clarify ODD_PARITY

This may need to be refined.

The variable ODD_PARITY is defined at various places,
with different values, causing compilation warnings.

It's wrong to define a variable with different values.

A new variable is created, specific to IMEI case: IMEI_ODD_PARITY.
Maybe ODD_PARITY should also have 0xf as value, and so maybe only
one variable is necessary. To be checked at some point...