Vibrator Service: Allow HAL Version Checking

Broke up the halCall() API into two components, one that implements the
initial service retrieval and one that implements the retry on
connection loss. This allows the service retrival API to double as test
for supported version with little overhead.

Test: Manually via CLI
Change-Id: I12cf8838e933187d473157c9576d1b13b03913d4
Signed-off-by: Harpreet \"Eli\" Sangha <eliptus@google.com>