cmUVProcessChain: Simplify builder initialization

Source/cmUVProcessChain.cxx

@@ -57,12 +57,7 @@ struct cmUVProcessChain::InternalData
   void Finish();
 };
 
-cmUVProcessChainBuilder::cmUVProcessChainBuilder()
-{
-  this->SetNoStream(Stream_INPUT)
-    .SetNoStream(Stream_OUTPUT)
-    .SetNoStream(Stream_ERROR);
-}
+cmUVProcessChainBuilder::cmUVProcessChainBuilder() = default;
 
 cmUVProcessChainBuilder& cmUVProcessChainBuilder::AddCommand(
   const std::vector<std::string>& arguments)

Source/cmUVProcessChain.h

@@ -50,8 +50,8 @@ private:
 
   struct StdioConfiguration
   {
-    StdioType Type;
-    int FileDescriptor;
+    StdioType Type = None;
+    int FileDescriptor = -1;
   };
 
   struct ProcessConfiguration