Fix command-not-found handling

fibonaccios/apploader.py

@@ -1,3 +1,5 @@
+from fibonaccios.exceptions import *
+
 _cache = {}
 
 def get_app(app):
@@ -6,7 +8,7 @@ def get_app(app):
     except KeyError:
         try:
             module = __import__(f'/bin/{app}')
-        except AttributeError:
+        except ImportError:
             raise AppNotFound(app)
 
         try: