[pshinter] Fully initialize globals->blues.
These defaults may be overriden later by psh_blues_scale_zones
which
is conditionally called from psh_globals_set_scale
.
- src/pshinter/pshglob.c (psh_globals_new): initialize
blues->blue_threshold
andblues->no_overshoots
.
Fixes: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=43701