avoid 'Use of uninitialized value in concatenation (.) or string at LedgerSMB/Report/Invoices/Outstanding.pm'

git-svn-id: svn://svn.code.sf.net/p/ledger-smb/code/trunk@5927 4979c152-3d1c-0410-bac9-87ea11338e46
Merge branch 'ledger14' into ledger14-dojo
Enhancements #15: Replace include_dojo with dojo_require (array of widgets and parsing support); and #14: add support for dojo_load, make string instead of array, call object's init() method