Make tests resilient to "ns not found" not being at the start of the error message

Author: jyemin

driver-async/src/test/functional/com/mongodb/async/client/Fixture.java

@@ -117,7 +117,7 @@ public static MongoCollection<Document> initializeCollection(final MongoNamespac
             database.runCommand(new Document("drop", namespace.getCollectionName()), futureResultCallback);
             futureResultCallback.get(60, SECONDS);
         } catch (MongoCommandException e) {
-            if (!e.getErrorMessage().startsWith("ns not found")) {
+            if (!e.getErrorMessage().contains("ns not found")) {
                 throw e;
             }
         } catch (Throwable t) {
@@ -141,7 +141,7 @@ public static void dropDatabase(final String name) {
                             .runCommand(new Document("dropDatabase", 1), futureResultCallback);
             futureResultCallback.get(60, SECONDS);
         } catch (MongoCommandException e) {
-            if (!e.getErrorMessage().startsWith("ns not found")) {
+            if (!e.getErrorMessage().contains("ns not found")) {
                 throw e;
             }
         } catch (Throwable t) {