Add a notion of "physical" sysroot, use for remote writing

Using `${sysroot}` to mean the physical storage root: We don't want to write to
`${sysroot}/etc/ostree/remotes.d`, since nothing will read it, and really
`${sysroot}` should just have `/ostree` (ideally). Today the Anaconda rpmostree
code ends up writing there. Fix this by adding a notion of "physical" sysroot.
We determine whether the path is physical by checking for `/sysroot`, which
exists in deployment roots (and there shouldn't be a `${sysroot}/sysroot`).

In order to unit test this, I added a `--sysroot` argument to `remote add`.
However, doing this better would require reworking the command line parsing for
the `remote` argument to support specifying `--repo` or `--sysroot`, and I
didn't quite want to do that yet in this patch.

Closes: https://github.com/ostreedev/ostree/issues/892

Closes: #896
Approved by: jlebon

tests/admin-test.sh

@@ -232,3 +232,19 @@ curr_rev=$(${CMD_PREFIX} ostree rev-parse --repo=sysroot/ostree/repo testos/buil
 assert_streq ${curr_rev} ${head_rev}
 
 echo "ok upgrade with and without override-commit"
+
+deployment=$(${CMD_PREFIX} ostree admin --sysroot=sysroot --print-current-dir)
+${CMD_PREFIX} ostree --repo=sysroot/ostree/repo --sysroot=sysroot remote add --set=gpg-verify=false remote-test-physical file://$(pwd)/testos-repo
+assert_not_has_file ${deployment}/etc/ostree/remotes.d/remote-test-physical.conf testos-repo
+assert_file_has_content sysroot/ostree/repo/config remote-test-physical
+echo "ok remote add physical sysroot"
+
+# Now a hack...symlink ${deployment}/sysroot to the sysroot in lieu of a bind
+# mount which we can't do in unit tests.
+ln -sr sysroot ${deployment}/sysroot
+ln -s sysroot/ostree ${deployment}/ostree
+ls -al ${deployment}
+${CMD_PREFIX} ostree --repo=sysroot/ostree/repo --sysroot=${deployment} remote add --set=gpg-verify=false remote-test-nonphysical file://$(pwd)/testos-repo
+assert_not_file_has_content sysroot/ostree/repo/config remote-test-nonphysical
+assert_file_has_content ${deployment}/etc/ostree/remotes.d/remote-test-nonphysical.conf testos-repo
+echo "ok remote add nonphysical sysroot"

tests/test-admin-deploy-grub2.sh

@@ -19,7 +19,7 @@
 
 set -euo pipefail
 
-echo "1..16"
+echo "1..18"
 
 . $(dirname $0)/libtest.sh
 

tests/test-admin-deploy-syslinux.sh

@@ -19,7 +19,7 @@
 
 set -euo pipefail
 
-echo "1..16"
+echo "1..18"
 
 . $(dirname $0)/libtest.sh
 

tests/test-admin-deploy-uboot.sh

@@ -20,7 +20,7 @@
 
 set -euo pipefail
 
-echo "1..17"
+echo "1..19"
 
 . $(dirname $0)/libtest.sh