Improve creating log directory

Change-Id: I1d3df0dbdb46df30b2e6467896e3a224cb7911a6
Reviewed-on: https://asterix-gerrit.ics.uci.edu/890
Reviewed-by: Till Westmann <tillw@apache.org>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
diff --git a/hyracks-fullstack/hyracks/hyracks-control/hyracks-nc-service/src/main/java/org/apache/hyracks/control/nc/service/NCService.java b/hyracks-fullstack/hyracks/hyracks-control/hyracks-nc-service/src/main/java/org/apache/hyracks/control/nc/service/NCService.java
index ea220c1..e3fe959 100644
--- a/hyracks-fullstack/hyracks/hyracks-control/hyracks-nc-service/src/main/java/org/apache/hyracks/control/nc/service/NCService.java
+++ b/hyracks-fullstack/hyracks/hyracks-control/hyracks-nc-service/src/main/java/org/apache/hyracks/control/nc/service/NCService.java
@@ -140,7 +140,10 @@
                 pb.redirectErrorStream(true);
                 File log = new File(config.logdir);
                 if (! log.mkdirs()) {
-                    throw new IOException(config.logdir + ": cannot create");
+                    if (! log.isDirectory()) {
+                        throw new IOException(config.logdir + ": cannot create");
+                    }
+                    // If the directory IS there, all is well
                 }
                 File logfile = new File(config.logdir, "nc-" + ncId + ".log");
                 pb.redirectOutput(ProcessBuilder.Redirect.appendTo(logfile));