Iceberg generates incorrect properties file

[JurajKubelka]

Please check this PR to understand the issue: Ducasse/Containers-PropertyEnvironment#2

Using the latest Pharo 7 and converting a repository from treefile to Tonel format generates this content:

{
 	#format : #tonel
 }e
 }

To convert it, I used Iceberg's menu option "convert to tonel".

I think I did it in:

Pharo 7.0.0
Build information: Pharo-7.0.0+alpha.build.1351.sha.f0b4d63e9c67d8b0fa9c68bd86613867d81ad45d (64 Bit)

[guillep]

Duplicates #1013

This will be integrated in today's release.