Test not running on German OS

[hendrikebbers]

Looks like a change in the near past (76cc096) breaks tests on a German system:

AllTests > org.bouncycastle.mail.smime.test.SignedMailValidatorTest.testKeyUsage FAILED
    junit.framework.ComparisonFailure: expected:<[The key usage extension of signer certificate does not permit using the key for email signatures].> but was:<[Der Schlüssel des Unterzeichners darf nicht für Email Signaturen verwendet werden].>
        at app//junit.framework.Assert.assertEquals(Assert.java:100)
        at app//junit.framework.Assert.assertEquals(Assert.java:107)
        at app//junit.framework.TestCase.assertEquals(TestCase.java:260)
        at app//org.bouncycastle.mail.smime.test.SignedMailValidatorTest.assertContainsMessage(Unknown Source)
        at app//org.bouncycastle.mail.smime.test.SignedMailValidatorTest.testKeyUsage(Unknown Source)

[dghgit]

We'd happily accept a PR to help fix this.

[dghgit]

So I think I've been able to emulate what's happening locally... try what's on github once commit 9af4ca9 shows up (hopefully in about 20 minutes) and let me know how it goes.