libdm: add an overload of DeleteDevice accepting a timeout_ms

In some scenarios (e.g. apexd or userspace reboot), dm-devices are
getting deleted and re-created. Since this operation can be racy (newly
created device can get the same path as the previously deleted one,
resulting in the unexpected ENOENT errors on a system call to the path),
it will be nice to have an API that blocks until ueventd processes
corresponding udev events.

Test: libdm_test
Bug: 143970043
Bug: 122059364
Change-Id: I31a19afd9e245bf5e3554011bdde1c3cc4878f1c