cli (blog/get): fix default output when a value is None

sat_frontends/jp/cmd_blog.py

@@ -366,7 +366,7 @@ class Get(base.CommandBase):
                 value = k_cb[k](item, keys) if k in k_cb else item[k]
                 if isinstance(value, bool):
                     value = str(value).lower()
-                self.disp(header + value)
+                self.disp(header + (value or ""))
                 # we want a separation line after each item but the last one
             if idx < len(items) - 1:
                 print("")