Patch from Scott McKellar, with modifications, to remove unused code and provide...

Patch from Scott McKellar, with modifications, to remove unused code and provide some memory protection:

This patch contains one minor change and one less minor change.

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The less minor change is the elimination of some old code that once
opened a pipe to send commands to bash.  According to Bill Erickson
in a private email, that code is a leftover remnant from an
experiment and may be removed.

Before a patch was applied several days ago, things worked like this:
IF you compiled srfsh with a certain macro #defined, AND you entered
a command that was invalid to srfsh, THEN srfsh would pipe the
command to bash for execution.

It is doubtful that anyone but Bill ever used this variation, but if
anyone wants to keep it around, then this is his or her chance to
protest.  Before protesting, however, please note that the shell
escape mechanism now provides shell-like command processing.  I.e.
if you start the srfsh command line with an exclamation point, srfsh
passes the rest of the command to the default shell (normally
/bin/sh) for execution.  The command so passed can use environmental
variables, pipes, IO redirection, wild card expansion, and most of
the sorts of things you're used to from the shell command line.

Note that not all shells behave the same.  If you're used to using
tcsh as your shell, for example, you may find that sh won't work
quite the same way.  For now, at least, that's just too bad, but
that's the way shell escapes typically work.

It is probably possible to invoke the user's default shell as
identified by the environmental variable $SHELL.  However that
nicety would not be trivial to code.

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The minor change is that, after building an array of pointers
pointing to tokens from the input command, I set the next
pointer to NULL so that it mark the end of the token list.

(miker: I changed to calloc/free instead of an array, but left the final
NULL in place.)

git-svn-id: svn://svn.open-ils.org/OpenSRF/trunk@1030 9efc2488-bf62-4759-914b-345cdb29e865