test: Remove explicit sleeps from ofproto-dpif bond tests

test: Remove explicit sleeps from ofproto-dpif bond tests

Ofproto-dpif bond tests relies on netdev-dummy ports to set up
socket connection before actual tests. The time required
for socket connection varies depends on system load, making the test
prone to failure with simple sleep calls. On the other hand,
conservative sleep value for the slowest machine may be excessive on
a faster machine.

This patch removes the sleep calls. Replace them with
WAIT_FOR_DUMMY_PORTS() introduced in the last patch, thus removing
the timing dependency.

CC: Jarno Rajahalme <jrajahalme@nicira.com>
Signed-off-by: Andy Zhou <azhou@nicira.com>
Acked-by: Jarno Rajahalme <jrajahalme@nicira.com>