qa: fix bash-ism in qa/661 causing lintian warnings
qa: fix bash-ism in qa/661 causing lintian warnings

Use consistent syntax for function declarations in 661, else
  $ sh -n qa/661
  qa/661: 57: qa/661: Syntax error: "(" unexpected

aeg-aeg/pcpfans,wuliming/pcp,aeg-aeg/pcpfans,prasincs/pcp,aeg-aeg/pcpfans,wuliming/pcp,edwardt/pcp,prasincs/pcp,tjanez/pcp,prasincs/pcp,wuliming/pcp,adfernandes/pcp,adfernandes/pcp,tjanez/pcp,prasincs/pcp,wuliming/pcp,adfernandes/pcp,adfernandes/pcp,wuliming/pcp,edwardt/pcp,edwardt/pcp,aeg-aeg/pcpfans,prasincs/pcp,wuliming/pcp,aeg-aeg/pcpfans,edwardt/pcp,adfernandes/pcp,adfernandes/pcp,aeg-aeg/pcpfans,edwardt/pcp,edwardt/pcp,edwardt/pcp,adfernandes/pcp,adfernandes/pcp,tjanez/pcp,prasincs/pcp,aeg-aeg/pcpfans,prasincs/pcp,edwardt/pcp,tjanez/pcp,tjanez/pcp,prasincs/pcp,wuliming/pcp,tjanez/pcp,wuliming/pcp,tjanez/pcp,tjanez/pcp,aeg-aeg/pcpfans