www: utils: Replace some strncpy with snprintf
www: utils: Replace some strncpy with snprintf

snprintf() is generally safer to use than strncpy() due to it always[0]
null terminating the string.

[0] - Unless the size argument is 0.

Signed-off-by: Andrew Clayton <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@opentechlabs.co.uk>

ac000/receiptomatic