configure: consider using /usr/include/openjpeg-1.5 when searching for openjpeg

Beginning with version 1.5.1 openjpeg defaults to install its headers to
/usr/include/openjpeg-${major}.${minor} instead of /usr/include without
providing a compatibility symlink making the old test fail.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>