Squashed 'subtree/rabit/' changes from e81a11d..bed6320

bed6320 Merge pull request #26 from DrAndrey/master
291ab05 Remove redundant whitespace again
de25163 Remove redundant whitespace
3a6be65 Fix bug with name of sleep function

git-subtree-dir: subtree/rabit
git-subtree-split: bed63208af736c4aa289b629fbe5396bd9f513d9

src/allreduce_base.cc

@@ -200,7 +200,11 @@ utils::TCPSocket AllreduceBase::ConnectTracker(void) const {
         utils::Socket::Error("Connect");
       } else {
         fprintf(stderr, "retry connect to ip(retry time %d): [%s]\n", retry, tracker_uri.c_str());
+        #ifdef _MSC_VER
+        Sleep(1);
+        #else
         sleep(1);
+        #endif
         continue;
       }
     }