Fix compiling with CUPS 2.2 backend.

cupsGetPPD() and cupsGetPPD2() have been moved into the cups/ppd.h
header starting with CUPS 2.2. This header file now needs to be included
to use these functions. The header file also exists on older versions of
CUPS, so a compile error will not occur.

R=skau@chromium.org, thestig@chromium.org

Review-Url: https://codereview.chromium.org/2258333004
Cr-Commit-Position: refs/heads/master@{#413484}
1 file changed