Can't export biomaterial information from biowells list

[Nicklas Nordborg]

Go to a bioplate with some biomaterial on it and switch to the 'Wells' tab. Use the 'Export' function and select at least one of the biomaterial columns. Enter a filename to make so that the exported data is saved in the BASE file system (immediate download will not work and doesn't display any error message).

net.sf.basedb.core.InvalidDataException: Path does not exist: BioWell.$mbm
  at net.sf.basedb.core.Metadata.getPropertyPath(Metadata.java:354)
  at net.sf.basedb.clients.web.plugins.ExportedProperty.parse(ExportedProperty.java:85)
  at net.sf.basedb.clients.web.plugins.SimpleExport.performExport(SimpleExport.java:291)
  at net.sf.basedb.core.plugin.AbstractExporterPlugin.run(AbstractExporterPlugin.java:144)
  at net.sf.basedb.core.PluginExecutionRequest.invoke(PluginExecutionRequest.java:116)
  at net.sf.basedb.core.PluginExecutionRequest.run(PluginExecutionRequest.java:141)
  at java.lang.Thread.run(Unknown Source)

[Nicklas Nordborg]

(In [6066]) Fixes #1700: Can't export biomaterial information from biowells list