[BUG] Rendering array concatenation broken

[kastoestoramadus]

Rendering adds quotes that break an entry with array concatenation.

Instead of expected this is generated:
except=${ex1}" "${ex2}

Which makes config unparsable. Parsing a rendered config should give back the same model as before rendering.

com.typesafe.config.ConfigException$WrongType: String: 1: Cannot concatenate object or list with a non-object-or-list, SimpleConfigList([1,2]) and Quoted(" ") are not compatible

	at com.typesafe.config.impl.ConfigConcatenation.join(ConfigConcatenation.java:124)
	at com.typesafe.config.impl.ConfigConcatenation.consolidate(ConfigConcatenation.java:161)
	at com.typesafe.config.impl.ConfigConcatenation.resolveSubstitutions(ConfigConcatenation.java:218)
	at com.typesafe.config.impl.ResolveContext.realResolve(ResolveContext.java:183)
	at com.typesafe.config.impl.ResolveContext.resolve(ResolveContext.java:146)
	at com.typesafe.config.impl.SimpleConfigObject$ResolveModifier.modifyChildMayThrow(SimpleConfigObject.java:371)
	at com.typesafe.config.impl.SimpleConfigObject.modifyMayThrow(SimpleConfigObject.java:304)
	at com.typesafe.config.impl.SimpleConfigObject.resolveSubstitutions(SimpleConfigObject.java:390)

failing test:
a524015