MSIM: Update persist.radio.airplane_mode_on property during APM change.

RIL uses persist.radio.airplane_mode_on property to check if sim
cards need to be powered down when telephony requests RADIO_POWER
OFF during boot up. So telephony needs to update this property
whenever there is a change in airplane mode.
Add the missing code to update the property in MSimPhoneGlobals.

Change-Id: Id5c6b8315ad8329b348a4e527e38e1d7c889bb03
CRs-Fixed: 661325