This patch documents the preference for g_new instead of g_malloc. The
reasons were adapted from commit b45c03f585ea9bb1af76c73e82195418c294919d.
Discussion in QEMU's mailing list:
http://lists.nongnu.org/archive/html/qemu-devel/2018-05/msg03238.html
Backports commit f7c922ed3d8e3cb54febbdc594ce9f4400e0d290 from qemu