system_app: grant read perms to sysfs_swap

Addresses:
avc: denied { read } for comm="SummaryLoader" name="mm_stat" dev="sysfs"
ino=10746 scontext=u:r:system_app:s0 tcontext=u:object_r:sysfs_swap:s0
tclass=file

Bug: 26990688
Change-Id: Iac92b0fd0275e2edf369fa8b9e10ec6b86384bd0
1 file changed