Give lmkd kill capability

lmkd needs the capability to kill processes.

Addresses the following denial:

<5>[12619.064604] type=1400 audit(1393540506.745:2565): avc:  denied  { kill } for  pid=116 comm="lmkd" capability=5  scontext=u:r:lmkd:s0 tcontext=u:r:lmkd:s0 tclass=capability

Addresses the following errors:

02-27 13:13:50.995   116   116 I lowmemorykiller: Killing 'com.google.android.deskclock' (7133), adj 15
02-27 13:13:50.995   116   116 I lowmemorykiller:    to free 33836kB because cache 118512kB is below limit 122880kB for oom_adj 15
02-27 13:13:50.995   116   116 I lowmemorykiller:    Free memory is -28472kB below reserved
02-27 13:13:50.995   116   116 E lowmemorykiller: kill(7133): errno=1

Change-Id: I7cca238610307aba9d77aa2e52a32ebd6aec3f3c