Added mbedtls_net_close and use it in ssl_fork_server to correctly
disassociate the client socket from the parent process and the server
socket from the child process.
diff --git a/library/net_sockets.c b/library/net_sockets.c
index 5d538bf..c7b358d 100644
--- a/library/net_sockets.c
+++ b/library/net_sockets.c
@@ -652,6 +652,19 @@
 }
 
 /*
+ * Close the connection
+ */
+void mbedtls_net_close( mbedtls_net_context *ctx )
+{
+    if( ctx->fd == -1 )
+        return;
+
+    close( ctx->fd );
+
+    ctx->fd = -1;
+}
+
+/*
  * Gracefully close the connection
  */
 void mbedtls_net_free( mbedtls_net_context *ctx )