Fix trivial spelling errors

- occured -> occurred
- reponse -> response
- seperated -> separated

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services, Inc.

versioning/BRM/oidserver.cpp

@@ -32,7 +32,7 @@
  * This class must implement a high degree of correctness.  However, it
  * also requires file IO.  Most functions throw an exception if a hard IO error
  * occurs more than MaxRetries times in a row.  Right now the code makes
- * no attempt to back out changes that occured before the error although it
+ * no attempt to back out changes that occurred before the error although it
  * may be possible to do so for certain errors.  Probably the best course of
  * action would be to halt the system if an exception is thrown here
  * to prevent database corruption resulting allocation of OIDs from a

versioning/BRM/slavenode.cpp

@@ -131,7 +131,7 @@ int ServiceWorkerNode::Child()
   catch (exception& e)
   {
     ostringstream os;
-    os << "An error occured: " << e.what();
+    os << "An error occurred: " << e.what();
     cerr << os.str() << endl;
     log(os.str());
     NotifyServiceInitializationFailed();

versioning/BRM/vbbm.cpp

@@ -664,7 +664,7 @@ void VBBM::getBlocks(int num, OID_t vbOID, vector<VBRange>& freeRanges, VSS& vss
         {
           ostringstream msg;
           msg << "VBBM::getBlocks(): version buffer overflow. Increase VersionBufferFileSize. Overflow "
-                 "occured in aged blocks. Requested NumBlocks:VbOid:vbFBO:lastFBO = "
+                 "occurred in aged blocks. Requested NumBlocks:VbOid:vbFBO:lastFBO = "
               << num << ":" << vbOID << ":" << firstFBO << ":" << lastFBO << " lbid locked is "
               << storage[i].lbid << endl;
           log(msg.str(), logging::LOG_TYPE_CRITICAL);