Don't call avb_property_lookup to get apex key name

Name of the public key is equal to the name of an apex module, there is
no need to call avb_property_lookup.

Test: atest CtsStagedInstallHostTestCases
Test: atest ApexTestCases
Test: atest --test-mapping system/apex/apexd:postsubmit
Bug: 146895998
Change-Id: I0be793b91ac904570145697dbf0ac540407d7195
6 files changed