1.4 is broken - Expression must be writeable

[304NotModified]

Unfortunately, there is a change that broke it.

On build we get:

Error		Fody: An unhandled exception occurred:
Exception:
Expression must be writeable
Parameter name: left
StackTrace:
   at System.Linq.Expressions.Expression.RequiresCanWrite(Expression expression, String paramName)
   at System.Linq.Expressions.Expression.Assign(Expression left, Expression right)
   at PropertyDelegateBuilder.TryBuildPropertySetDelegate[T](Type targetType, String propertyName, Action`2& action) in C:\projects\fody\FodyIsolated\DelegateBuilders\PropertyDelegateBuilder.cs:line 23
   at DelegateBuilder.BuildDelegateHolder(Type weaverType) in C:\projects\fody\FodyIsolated\DelegateBuilders\DelegateBuilder.cs:line 31
   at DelegateBuilder.GetDelegateHolderFromCache(Type weaverType) in C:\projects\fody\FodyIsolated\DelegateBuilders\DelegateBuilder.cs:line 15
   at InnerWeaver.InitialiseWeavers() in C:\projects\fody\FodyIsolated\InnerWeaver.cs:line 127
   at InnerWeaver.Execute() in C:\projects\fody\FodyIsolated\InnerWeaver.cs:line 82
Source:
System.Core
TargetSite:
Void RequiresCanWrite(System.Linq.Expressions.Expression, System.String)