CSHARP-2147: Add missing dependency to MongoDB.Driver.Core.nuspec.

Author: rstam

build/MongoDB.Driver.Core.nuspec

@@ -22,6 +22,7 @@
         <dependency id="NETStandard.Library" version="[1.6.1, )" />
         <dependency id="System.Collections.Specialized" version="[4.0.1, )" />
         <dependency id="System.Diagnostics.TraceSource" version="[4.0.0, )" />
+        <dependency id="System.Diagnostics.TextWriterTraceListener" version="[4.0.0, )" />
         <dependency id="System.Net.NameResolution" version="[4.3.0, )" />
         <dependency id="System.Net.Security" version="[4.0.0, )" />
         <dependency id="System.Security.SecureString" version="[4.0.0, )" />

src/MongoDB.Driver.Core.Dotnet/MongoDB.Driver.Core.Dotnet.csproj

@@ -18,17 +18,14 @@
     <Compile Include="..\MongoDB.Driver.Core\**\*.cs;..\MongoDB.Shared\ApplicationNameHelper.cs;..\MongoDB.Shared\Hasher.cs;..\MongoDB.Shared\MaxTimeHelper.cs" Exclude="bin\**;obj\**;**\*.xproj;packages\**" />
   </ItemGroup>
 
-  <ItemGroup>
-    <PackageReference Include="System.Diagnostics.TextWriterTraceListener" Version="4.0.0" />
-  </ItemGroup>
-
   <ItemGroup>
     <ProjectReference Include="..\MongoDB.Bson.Dotnet\MongoDB.Bson.Dotnet.csproj" />
   </ItemGroup>
 
   <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard1.5' ">
     <PackageReference Include="System.Collections.Specialized" Version="4.0.1" />
     <PackageReference Include="System.Diagnostics.TraceSource" Version="4.0.0" />
+    <PackageReference Include="System.Diagnostics.TextWriterTraceListener" Version="4.0.0" />
     <PackageReference Include="System.Net.NameResolution" Version="4.3.0" />
     <PackageReference Include="System.Net.Security" Version="4.0.0" />
     <PackageReference Include="System.Security.SecureString" Version="4.0.0" />