get-bugzilla-attachments: avoid FDO-TDF duplicates...
get-bugzilla-attachments: avoid FDO-TDF duplicates...

... by checking that a file with "fdo" already exists for bugs older
than the migration, instead of just ignoring the old bugs on TDF.

There are > 300 additional attachments not on freedesktop.org.

Change-Id: Ib7ee63041109071cc1241a875ef2cccbddfc699d

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