This is a followup to commit b0fd2bd.
* gnu/packages/gawk.scm (gawk)[arguments] <install-locales>: Add comment
on why we leave this here.
* gnu/packages/guile.scm (guile-ncurses)[arguments]: Remove
'install-locales' phase.
* gnu/packages/swig.scm (swig)[arguments]: Likewise.
* gnu/packages/python.scm (python-matplotlib): Remove 'LOCPATH' setting
and 'localedef' invocation.
(python-scipy): Likewise.
* gnu/packages/swig.scm (swig): Disable input python. Before, it was not
taken into account during configure; now that it is found, it fails
its tests. None of the dependent packages need it.