REDHAT-BUG-2502799: Medium severity OpenPrinting libcupsfilters vulnerability

libcupsfilters through 2.1.1 contains a denial-of-service flaw in cfIEEE1284NormalizeMakeModel() in cupsfilters/ieee1284.c. When processing an IEEE-1284 device ID with an empty MDL field, modelptr equals buffer after copying zero model characters, causing the dedup loop at line 1122 to call strncasecmp(buffer, modelptr, 0) which always returns 0 and moverightpart(buffer, bufsize, modelptr, 0) which makes no progress. The loop never terminates and pins one CPU core indefinitely. The function is reachable over the network via cfIEEE1284GetMakeModel() called by cups-browsed on printer-advertised device IDs (IPP/DNS-SD). CWE-835. No upstream fix; PR #139 / commit 7c45e5f addresses an adjacent OOB-read only.