Remove some getDevice().waitForDeviceAvailable()s

Remove getDevice().waitForDeviceAvailable() that follows
getDevice().reboot() for reboot() has called waitForDeviceAvailable()
internally.

See b/143114522 #1 for more details.

Bug: 143114522
Test: atest StagedRollbackTest
Change-Id: I19d3648947435b8d5a10d09736b170fd8be8be47
1 file changed