Fix: segfault when connecting to a server with cg_oversampleMouse 1

[metaq3]

Simple correction for native builds and overall code sanity.

How to reproduce:

• Start quake with native library loaded, e.g. with sv_pure 0 and vm_cgame 0
• Set cg_oversampleMouse to 1 and /devmap any map or connect to any server
• Observe kernel sending signal 11 ( SIGSEGV ) to your quake instance

Why

With cg_oversampleMouse 1 client prediction calls PM_UpdateViewAngles, which, in turn, uses nullish pm. This is only the first frame, so Pmove, which updates pm to valid pmove, has not been called yet, so pm is NULL.

It's clear that this is an oversight, all the other code of the func uses ps provided in the args, not pm->ps.

[snems]

OSP 1.03 also uses ps. Thanks!