Remove redundant file from Java build

svn path=/trunk/mcs/; revision=87640

mcs/class/System.Configuration/System.Configuration20.csproj

@@ -183,7 +183,6 @@
     <Compile Include="System.Configuration\IgnoreSection.cs" />
     <Compile Include="System.Configuration\InfiniteIntConverter.cs" />
     <Compile Include="System.Configuration\InfiniteTimeSpanConverter.cs" />
-    <Compile Include="System.Configuration\IntegerConfigurationProperty.cs" />
     <Compile Include="System.Configuration\IntegerValidator.cs" />
     <Compile Include="System.Configuration\IntegerValidatorAttribute.cs" />
     <Compile Include="System.Configuration\InternalConfigurationFactory.cs" />