Explicitly label filesystem files in /proc

proc files needed by fwk that were labeled:
/proc/filesystems -> proc_filesystems
/proc/mounts -> proc_mounts
/proc/swaps -> proc_mounts

Removed access to proc label from these domains:
e2fs, fsck, fsck_untrusted, sdcardd

e2fs: added access to proc_filesystems, proc_mounts, proc_swaps
fsck: added access to proc_mounts, proc_swaps
fsck_untrusted: added access to proc_mounts
sdcardd: added access to proc_filesystems
vold: added access to proc_filesystems, proc_mounts

Bug: 66199084
Test: device boots without selinux denials to new labels or proc label.
Change-Id: If0f19e22074419dab0b3a0c6f3a300ea8cb94523