Don't set MSG_NOSIGNAL when receiving or reading

The flag is for sending. It's a no-op for receiving. If connection is
lost during the call, you get ECONNRESET, not a SIGPIPE or EPIPE.

Bug: N/A
Flag: EXEMPT code clean-up
Test: watch TH

Change-Id: Iaa6d3e317e22687d64ad3d6d8646958b26e74227