Merge pull request #1339 from txdv/git-clone-options-field

Remove obsolete field.

Author: carlosmn

LibGit2Sharp/Core/GitCloneOptions.cs

@@ -23,8 +23,6 @@ internal struct GitCloneOptions
         public GitCloneLocal Local;
         public IntPtr CheckoutBranch;
 
-        public IntPtr signature; // Really a SignatureSafeHandle
-
         public IntPtr RepositoryCb;
         public IntPtr RepositoryCbPayload;