BUG: fftpack: fix data overwriting in FFT routines (#1353)
BUG: fftpack: fix data overwriting in FFT routines (#1353)

The _fix_shape helper routine in some cases returns slices of the input
array, which does not create copies. In those cases, one should not set
overwrite_x=1.

git-svn-id: 003f22d385e25de9cff933a5ea4efd77cb5e7b28@7110 d6536bca-fef9-0310-8506-e4c0a848fbcf

jasonmccampbell/scipy-refactor,lesserwhirls/scipy-cwt,scipy/scipy-svn,jasonmccampbell/scipy-refactor,lesserwhirls/scipy-cwt,lesserwhirls/scipy-cwt,lesserwhirls/scipy-cwt,jasonmccampbell/scipy-refactor,scipy/scipy-svn,jasonmccampbell/scipy-refactor,scipy/scipy-svn,scipy/scipy-svn