Do not expand hal_audio attribute

Fixes:
neverallow hal_audio domain:{ tcp_socket udp_socket rawip_socket } *;
Warning!  Type or attribute hal_audio used in neverallow undefined in
policy being checked.

hal_audio_client is not used in neverallows and was mistakenly marked
as expandattribute false instead of hal_audio. Fix this.

Bug: 63809360
Test: build policy
Test: cts-tradefed run cts -m CtsSecurityHostTestCases -t \
    android.cts.security.SELinuxNeverallowRulesTest

    No more:
    Warning!  Type or attribute hal_audio used in neverallow
    undefined in policy being checked.

Change-Id: Iedf1b80f669f95537ed201cbdbb0626e7e32be81