Fix EINTR handling in _LSTransportRecvFd

:Release Notes:
Fix EINTR error handling while trying to get file
descriptor after corresponding incoming message.

:Detailed Notes:
Client can get 'interrupted system call' (EINTR) error
during 'recvmsg' call. This is not a critical error, so
we can try to recieve the message again.

:Testing Performed:
Unit tests, miniBAT.

:QA Notes:

:Issues Addressed:
[GF-43064] LS2 client side does not handle EINTR correctly outside GMainLoop

Open-webOS-DCO-1.0-Signed-off-by: Alexandr Smoktal <alexandr.smoktal@lge.com>

Change-Id: I37b19cbbd6f60479b083a1ac03259ee7aa058fc4
Reviewed-on: https://g2g.palm.com/4336
Reviewed-by: DCO Verification
Reviewed-by: Alexandr Smoktal <alexandr.smoktal@lge.com>
Tested-by: Alexandr Smoktal <alexandr.smoktal@lge.com>
Reviewed-by: Anatoliy Klymenko <anatoliy.klimenko@lge.com>
Tested-by: Anatoliy Klymenko <anatoliy.klimenko@lge.com>
Reviewed-by: Anatolii Sakhnik <anatolii.sakhnik@lge.com>