[rilmodem] Check and set tech prefence as configured

After flashing modem uses default technology preference of it's
own. This fix forces it to 3G/2g only, if configuration is set
so.

Signed-off-by: Jussi Kangas <jussi.kangas@oss.tieto.com>
Merge pull request #100 from jkangas/master

Request for pulling technology preference checking and setting at startup to main branch
[rilmodem] Release parcel after message sending

Parcel needs to be released after message sending. Otherwise
there is a minor memory leak.

Signed-off-by: Jussi Kangas <jussi.kangas@oss.tieto.com>
[rilmodem] When sim stays on in offline mode PIN cache can be emptied

After modem is configured to keep SIM alive in offline mode PIN
cache can and should be tied to SIM presence notification. Note:
inserting this fix before modem configuration change will
effectively break PIN caching part of the hidden reset.

Signed-off-by: Jussi Kangas <jussi.kangas@oss.tieto.com>
Merge pull request #101 from jkangas/master

Request for pulling PIN cache emptying when sim removed and minor bug fix to main branch

Reviewed and approved by marttipiirainen, tkenakka and me. Merging..