fixed error in ConvertFlowUnits.Rd example


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/ecohydrology@206 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
fixed a couple of errors in code - Jo

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/ecohydrology@207 edb9625f-4e0d-4859-8d74-9fd3b1da38cb