bug#18108: 24.3.92 : eshell-visual-options fails with some output.

[Charles Rendleman]

1) emacs -Q

2) invoke eshell

The following inputs are at the eshell prompt.

3) git --help                                     # shows git help summary

3') *git --help                                   # shows git help summary

4) (add-to-list 'eshell-visual-options '("git" "--help"))

5) git --help                                     # shows nothing

6) bash -c "git --help"                      # shows git help summary

7) *git --help                                    # displays '/bin/git: external command failed'

8) git --version                                 # displays "git version 2.0.2"