log failure to import plugins or plot module

electrum/plugin.py

@@ -132,7 +132,8 @@ class Plugins(DaemonThread):
         for dep, s in deps:
             try:
                 __import__(dep)
-            except ImportError:
+            except ImportError as e:
+                self.print_error('Plugin', name, 'unavailable:', type(e).__name__, ':', str(e))
                 return False
         requires = d.get('requires_wallet_type', [])
         return not requires or w.wallet_type in requires