Fixed a unexpected script terminating issue.
Fixed a unexpected script terminating issue.

When the server process get crashed, because the bug collector need to upload the crash dump (which may take some time), some files in the running log dir will be locked for awhile. Those locked file will cause the script get exited and left server stuck there. This modification intend to avoid this situation: Now the script will keep retry, and restart the server after the bug collector finished it's uploading job.

s117/NS2-Server-Watchdog