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_python.c b/src/if_python.c
index 812497a..7319382 100644
--- a/src/if_python.c
+++ b/src/if_python.c
@@ -1575,6 +1575,7 @@
 	case VAR_SPECIAL:
 	case VAR_JOB:
 	case VAR_CHANNEL:
+	case VAR_BLOB:
 	    break;
     }
 }