Make version check in gdb_rust_pretty_printing.py more compatible.
Make version check in gdb_rust_pretty_printing.py more compatible.

Some versions of Python don't support the `major` field on the
object returned by `sys.version_info`.

GBGamer/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,graydon/rust,graydon/rust,aidancully/rust,GBGamer/rust,graydon/rust,graydon/rust,GBGamer/rust