Patch from Scott McKellar to fix potential local buffer

Patch from Scott McKellar to fix potential local buffer
overflow attack against srfsh:

This patch fixes a potential buffer overflow in the parse_error
function.  The existing code concatenates the strtoked tokens into a
fixed-length buffer, with no check for overflow.  It isn't hard to
build an srfsh command that overflows the buffer, with baleful
results.

While it's not likely that anyone would do so by accident from the
command line, an srfsh script might well do so, especially if the
script were generated from another program.

More important, someone sufficiently clever might be able to use
such an overflow to work mischief.

My version of parse_error() uses a growing_buffer to accumulate
the tokens.

git-svn-id: svn://svn.open-ils.org/OpenSRF/trunk@1022 9efc2488-bf62-4759-914b-345cdb29e865