Inform checkfc about new service label backend.

Test: bullhead builds

Bug: 31353148
Change-Id: I499da36108e67483a4f9a18fd8cc7c8f13419abd

Checkfc was treating 0 size fc files as a fatal error.
An empty fc file should be treated as "nothing to check"
so long as the -e option is passed.

We add this option, so we don't allow empty file_context
files to pass CTS checking.

Change-Id: Ibca6bd948a13389e10c605d613acc48c5504443e
Signed-off-by: William Roberts <william.c.roberts@intel.com>

Enable checkfc to check *_contexts against a set of valid attributes
which must be associated with all types in the contexts file that
is being checked.

Since it's imperative that checkfc knows which file its checking to
choose the proper attribute set, the -s option is introduced to
indicate the service_contexts file. The property_contexts file continues
to use the existing -p and file_contexts requires no specification, aka
it's the default.

Failure examples:
file_contexts:
Error: type "init" is not of set: "fs_type, dev_type, file_type"

service_contexts:
Error: type "init_exec" is not of set: "service_manager_type"

property_contexts:
Error: type "bluetooth_service" is not of set: "property_type"

Change-Id: I62077e4d0760858a9459e753e14dfd209868080f
Signed-off-by: William Roberts <william.c.roberts@intel.com>

Extend checkfc to support comparing two file_contexts or
file_contexts.bin files.  This is for use by the CTS
SELinuxHostTest to compare the AOSP general_file_contexts
with the device file_contexts.bin file.

Depends on I0fe63e0c7f11ae067b5aac2f468f7842e5d76986.

Change-Id: I2fff2f8cf87690a76219ddf4cf38939650f34782
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>

Change-Id: If361ea93fabd343728196eed2663fd572ecaa70b
Signed-off-by: Robert Craig <rpcraig@tycho.ncsc.mil>

Change-Id: I57b0dd9f8071eae492020f410c87f465ba820711

Change-Id: I4b12dc3dcb432edbdf95dd3bc97f809912ce86d1
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>