Use PLOG and TEMP_FAILURE_RETRY for uevent socket errors

Use TEMP_FAILURE_RETRY() for recvmsg() to prevent failing
unnecessarily from EINTR.  Use PLOG(ERROR) in ueventd to display the
actual error if reading from the uevent socket does fail.

Test: build
Change-Id: I64a22698ce6ffc7573f75b57803551c7b6940e30