fix cross-resource dropbox move metadata error
fix cross-resource dropbox move metadata error

 * For intra_move and intra_copy, dropbox metadata figures out the relative path
   of the file by stripping the parent folder from the full path.  When
   moving a file from one node's dropbox to another's, we were
   inadvertantly passing the source's parent folder to the destination's
   meta object, causing nothing to be stripped and the full path to be
   returned.  Now we pass the destination's parent folder to the meta,
   and the file is properly made relative.

Johnetordoff/waterbutler,TomBaxter/waterbutler,RCOSDP/waterbutler,felliott/waterbutler,rdhyee/waterbutler,CenterForOpenScience/waterbutler