Update server version checks from 2.7 to 2.8, as the final release of the driver need not support the 2.7 development branch.

Author: jyemin

src/main/com/mongodb/DBApiLayer.java

@@ -148,7 +148,7 @@ public Set<String> getCollectionNames() {
         requestStart();
         try {
             List<String> collectionNames = new ArrayList<String>();
-            if (isServerVersionAtLeast(asList(2, 7, 7))) {
+            if (isServerVersionAtLeast(asList(2, 8, 0))) {
                 CommandResult res = command(new BasicDBObject("listCollections", getName()), ReadPreference.primary());
                 if (!res.ok() && res.getCode() != 26) {
                     res.throwOnError();

src/main/com/mongodb/DBCollectionImpl.java

@@ -342,7 +342,7 @@ public List<DBObject> getIndexInfo() {
         try {
             List<DBObject> list = new ArrayList<DBObject>();
 
-            if (db.isServerVersionAtLeast(asList(2, 7, 6))) {
+            if (db.isServerVersionAtLeast(asList(2, 8, 0))) {
                 CommandResult res = _db.command(new BasicDBObject("listIndexes", getName()), ReadPreference.primary());
                 if (!res.ok() && res.getCode() == 26) {
                     return list;

src/main/com/mongodb/DBPort.java

@@ -364,7 +364,7 @@ CommandResult authenticate(Mongo mongo, final MongoCredential credentials) {
         Authenticator authenticator;
         MongoCredential actualCredentials;
         if (credentials.getMechanism() == null) {
-            if (mongo.getConnector().getServerDescription(getAddress()).getVersion().compareTo(new ServerVersion(2, 7)) >= 0) {
+            if (mongo.getConnector().getServerDescription(getAddress()).getVersion().compareTo(new ServerVersion(2, 8)) >= 0) {
                 actualCredentials = MongoCredential.createScramSha1Credential(credentials.getUserName(), credentials.getSource(),
                                                                               credentials.getPassword());
             } else {