Incompatibility in dl1ab between before and after lstmcpipe v0.11

The change in data organisation at DL1 level 
```
/fefs/aswg/data/mc/DL1/AllSky/PROD_ID/TrainingDataset/GammaDiffuse/dec_XXXX/NODE
```
vs
```
/fefs/aswg/data/mc/DL1/AllSky/PROD_ID/TrainingDataset/dec_XXXX/GammaDiffuse//NODE
```
makes DL1ab incompatible between versions, so productions made before lstmcpipe v0.11 have to be treated with lstmcpipe < v0.11 