patch 8.1.0735: cannot handle binary data

Problem:    Cannot handle binary data.
Solution:   Add the Blob type. (Yasuhiro Matsumoto, closes #3638)
diff --git a/src/if_py_both.h b/src/if_py_both.h
index 1c15926..0b8a360 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -867,6 +867,10 @@
 	}
 	return ret;
     }
+    else if (our_tv->v_type == VAR_BLOB)
+	ret = PyBytes_FromStringAndSize(
+		(char*) our_tv->vval.v_blob->bv_ga.ga_data,
+		(Py_ssize_t) our_tv->vval.v_blob->bv_ga.ga_len);
     else
     {
 	Py_INCREF(Py_None);
@@ -6394,6 +6398,10 @@
 				tv->vval.v_partial->pt_argc, argv,
 				tv->vval.v_partial->pt_dict,
 				tv->vval.v_partial->pt_auto);
+	case VAR_BLOB:
+	    return PyBytes_FromStringAndSize(
+		(char*) tv->vval.v_blob->bv_ga.ga_data,
+		(Py_ssize_t) tv->vval.v_blob->bv_ga.ga_len);
 	case VAR_UNKNOWN:
 	case VAR_CHANNEL:
 	case VAR_JOB: