fix exception in DbGridColumn::impl_toggleScriptManager_nothrow
fix exception in DbGridColumn::impl_toggleScriptManager_nothrow

The messages would look like this:
  warn:legacy.osl:28639:1:svx/source/fmcomp/gridcell.cxx:255: caught an exception!

I introduced this bug in commit 6a043e9c0acff20e1618ca8ec15c21d5d0fd0d37
"Use the new type-checking Reference constructor to reduce code noise"

Change-Id: I922d46f7c7eefbc12892a2525b30dcb798619a8b

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core