Starting with commit 770d1a4502 ("isolation: Initially Keep
CAP_SETFCAP if running as UID 0 in non-init"), the lack of this rule
became more apparent as pasta needs to access uid_map in procfs even
as non-root.
However, both passt and pasta needs this, in case they are started as
root, so add this directly to passt's abstraction (which is sourced
by pasta's profile too).
Fixes: 770d1a4502 ("isolation: Initially Keep CAP_SETFCAP if running as UID 0 in non-init")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>