better error message when cfg file does not exist

frappyman.py

@@ -23,7 +23,7 @@
 import sys
 import os
 from glob import glob
-from os.path import join, isdir, basename, expanduser
+from os.path import join, isdir, basename, expanduser, exists
 from configparser import ConfigParser
 from servicemanager.base import ServiceManager, ServiceDown, UsageError
 
@@ -51,7 +51,13 @@ class FrappyManager(ServiceManager):
         cfgparser.optionxform = str
         cfgfile = self.env[ins]['FRAPPY_CONFIG_FILE'].replace('<SERV>', service)
         cfgparser.read(cfgfile)
-        for cfgpath in cfgparser['FRAPPY']['confdir'].split(os.pathsep):
+        try:
+            section = cfgparser['FRAPPY']
+        except KeyError:
+            if exists(cfgfile):
+                raise KeyError('%s has no FRAPPY section' % cfgfile)
+            raise FileNotFoundError('%s does not exist' % cfgfile)
+        for cfgpath in section['confdir'].split(os.pathsep):
             if cfgpath.endswith('<SERV>'):
                 cfgpaths.append(cfgpath[:-6] + service)
             else: