Properly reset global_options to global_options_base prior to each action
Properly reset global_options to global_options_base prior to each action

This modification fixes a bug in which options specified for the first
of several actions would "leak through" to the subsequent actions.
For example, prior to this fix:
  > port info --variants emacs \; info --homepage pango
  variants: darwin_7, x11, motif, gtk, carbon, atsui, universal
  homepage: http://www.pango.org/
  variants: no_x11, universal
  >
And after this fix:
  > port info --variants emacs \; info --homepage pango
  variants: darwin_7, x11, motif, gtk, carbon, atsui, universal
  homepage: http://www.pango.org/
  >

git-svn-id: 620571fa9b4bd0cbce9a0cf901e91ef896adbf27@44339 d073be05-634f-4543-b044-5fe20cf6d1d6

danchr/macports-base,macports/macports-base,neverpanic/macports-base,danchr/macports-base,macports/macports-base,neverpanic/macports-base