Bug 5681: Fixes leading zeroes in Add Mulpiple Copies

Bug 5681: Fixes leading zeroes in Add Mulpiple Copies

From Biblibre:
I don't know why, but removing sprintf solves the problems with leading zeroes
and the problems with large values.

(written by jean-andré santoni)

Note from Chris:

The width is never set, so the sprintf always defaults to a float, which
trims the leading zeros. I am not smart enough to figure out how to set
a valid width when calling it, and removing the sprintf seems to work
See http://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=5681 for
test results

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>