Fix 3 issues reported by Coverity

Coverity scans Haiku's source code looking for issue and creates a report. This report may shows hundreds of potential issues. Figure out the correct fix for three of the listed issues and submit patches. The patches will then be reviewed for correctness and credit given. If you want to submit more than 3, that is fine as well, and may speed up the review/credit process as there are likely to be fewer false positives or incorrect fixes.

Further details

• Create a Coverity account at ​http://scan.coverity.com and request contributor access to the haiku project there.
• Once that is done, you will be able to view the CIDs and select one or more to work on.
• Change the filter settings to only show "Currently Detected" CIDs. Beware of false positives - sometimes Coverity's analysis doesn't understand Haiku code intentions.
• Once you locate one you wish to fix, please make sure it is not a false positive, make sure the fix addresses the problem (not the symptom), and submit a patch on our Bug Tracker at ​http://dev.haiku-os.org with a keyword gci2015.
• The patch and trac ticket should mention the CID, and should be created with git format-patch per our patch submission guildelines at ​http://dev.haiku-os.org/wiki/SubmittingPatches
• There is also a brief page on Haiku's Coverity usage here: ​http://dev.haiku-os.org/wiki/Coverity
• Feel free to join #haiku on irc/freenode if you need further assistance.