sigpipe: if mbedTLS is used, ignore SIGPIPE

mbedTLS doesn't have a sigpipe management. If a write/read occurs when
the remote closes the socket, the signal is raised and kills the
application.  Use the curl mecanisms fix this behavior.

Signed-off-by: Jeremie Rapin <j.rapin@overkiz.com>

Closes #3502