Revision 2518

Will create the tempDirectory if it is missing.

this is useful if, for example, you switch the tmp directory from
webwork2/courses/courseName/html/tmp  to something like

/ww/htdocs/tmp/courseName

You don't want to create a courseName node for every course, you would
prefer to create only /ww/htdocs/tmp

the current version will create the node courseName if it doesn't exist
(or the name tmp in the first example) but will not create files
higher up the tree.