Add SIGPIPE retry handling to child data sysread

Add SIGPIPE retry handling to child data sysread

Similar to the SIGPIPE retry logic wrapped around the parent process'
syswrite call (for sending data to a child process), protect the child's
sysread call (as it reads data from the parent).  In pre-2.0, the
sysread step was handled by Net::Server, but now we need to protect it
ourselves.

Signed-off-by: Bill Erickson <berick@esilibrary.com>