debfile: Pass `Name` instead of `Binary` to ExtractTar

Passing the binary causes it to fail trying to find the `false`
compressor when a binary for a given compressor is not installed.

Gbp-Dch: full
LP: #1926437

python/arfile.cc

@@ -600,7 +600,7 @@ static PyObject *debfile_get_tar(PyDebFileObject *self, const char *Name)
         Member = AR.FindMember(std::string(Name).append(c->Extension).c_str());
         if (Member == NULL)
             continue;
-        Compressor = c->Binary;
+        Compressor = c->Name;
         break;
     }