small fix to flux bcs.


git-svn-id: svn://svn.code.sf.net/p/elmerfem/code/trunk@7088 04224531-1f84-46d8-96ce-875b9e37dce3
still 'bout the flux bcs.


git-svn-id: svn://svn.code.sf.net/p/elmerfem/code/trunk@7089 04224531-1f84-46d8-96ce-875b9e37dce3