Remove PartitionMounter.

This dependency is only used in recovery, and it is adding extra complication
to VintfObject. Instead, RecoveryFilesystem should handle the mounting in
recovery.

Test: libvintf_test
Test: manual sideload
Bug: 118635062
Change-Id: Ife8b650e5bb06d8b37a7ee7b14f2fd78b1892876
8 files changed