NPE in CircuitBreaker, wrong null check

[AbelPelser]

In CitcuitBreakerRetryPolicy:121 the performed null check checks the wrong member, it should check openTimeoutSupplier. This causes NPEs if resetTimeoutSupplier is not null but openTimeoutSupplier is, which happens if a @CircuitBreaker has a resetTimeoutExpression and no openTimeoutExpression.

[artembilan]

Confirmed.
The code is like this:

		if (this.resetTimeoutSupplier != null) {
			resetTimeout = this.resetTimeoutSupplier.get();
		}
		long openTimeout = this.openTimeout;
		if (this.resetTimeoutSupplier != null) {
			openTimeout = this.openTimeoutSupplier.get();
		}

Which is really wrong.
Feel free to contribute the fix.

Thank you!

[AbelPelser]

Done, see #404