FoFiType1C::cvtGlyph: Fix uninitialized memory read on broken files

oss-fuzz/29269
7 jobs for type1cfixes in 8 minutes and 39 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #6465005
build

00:04:59

passed #6465010
build_android

00:00:48

passed #6465006
build_clang_libcpp

00:08:39

passed #6465009
build_clazy

00:04:39

passed #6465008
build_mingw64_fedora

00:05:20

passed #6465007
build_ubuntu_16_04

00:02:23

passed #6465004
clang_format

00:03:40