cupsfilter hangs with 100% cpu usage with corrupted gif

[ocean1]

Potential denial of service in cupsfilter (through imagetopdf) with the following corrupted gif
1051.gif.zip.

Reproducible with: cupsfilter 1051.gif

[dheeraj135]

@ocean1 I was able to reproduce this error in the latest version of cups-filters. I think, when the input file is corrupted, the program should exit gracefully rather than a segfault.