Fixes for some issues found using Coverity

[Greg Hudson]

On 03/30/2017 04:17 AM, Kittel, Martin wrote:
> We still have quite a number of Coverity messages to go through and I was wondering whether you are interested in more patches from our side.

Sure, please go ahead and submit more changes.  There is sometimes a
tension between making static analysis tools happy and making the code
look natural to a human reader, but in most cases there is a good
compromise.