Missing aliases file causes AttributeError

[neil-greenwood]

If the .mutt/aliases file does not exist, the following error is thrown if the mutt_alias helper is configured:

$ muttqt -q Joe
Traceback (most recent call last):
  File "/usr/local/bin/muttqt", line 754, in <module>
    sys.exit(main())
  File "/usr/local/bin/muttqt", line 723, in main
    aliasDat.searchData(query)
  File "/usr/local/bin/muttqt", line 56, in searchData
    for l in self.data:
AttributeError: 'aliasData' object has no attribute 'data'