qmuxd: fix denial related to capability

Fix the following denial

Allow qmuxd to have the CAP_BLOCK_SUSPEND capability

[   47.694567] type=1400 audit(1413464098.587:1914): avc: denied
{ block_suspend } for pid=1074 comm="qmuxd" capability=36
scontext=u:r:qmuxd:s0 tcontext=u:r:qmuxd:s0 tclass=capability2
permissive=0

CRs-Fixed: 740553
Change-Id: I39a1239f399b7d37709bac323594db2451e1b93c