pulseaudio: Fix detection of ALSA UCM

This one was a bit tricky to find because it only causes a runtime
error, and pulseaudio has shims for most ALSA UCM methods except one.
(I guess nobody ever really tests pulseaudio in combination with
UCM-less ALSA?)

ALSA 1.1.8 had ${alsa-dev}/include/alsa/ in the pkg-config file, which
was considered wrong and fixed in 1.1.9.

However, pulseaudio was relying on being able to include ALSA headers
like <asoundlib.h> and <use-case.h> rather than <alsa/asoundlib.h> and
<alsa/use-case.h>. (For asoundlib.h it only causes a warning, because
the ALSA guys created a shim for that header.)

These two patches change pulseaudio to use the correct include
directives.