Relax membership assertion for the prefix test.

Relaxes the membership check in prefix testing. The check is no longer
sensitive to ordering of the results, as different providers may
append, prepend, or insert in sorted order the relative prefixes.

blobstore/src/test/java/org/jclouds/blobstore/integration/internal/BaseContainerLiveTest.java

@@ -144,7 +144,7 @@ public class BaseContainerLiveTest extends BaseBlobStoreIntegrationTest {
          names.add(sm.getName());
       }
 
-      assertThat(names).containsExactlyElementsOf(expectedSet);
+      assertThat(names).containsOnlyElementsOf(expectedSet);
    }
 
    private void runCreateContainerInLocation(String payload, Location nonDefault) throws InterruptedException,