podman-registry: many unrelated fixes

1) fix lost credentials.

    must_pass(), added in #6375, eats the credentials
    generated via 'podman run --entrypoint htpasswd'.
    Run that podman instance directly, and add explicit
    error check.

    (The error and stdout/stderr handling here has gotten
    cumbersome. There must be something I'm missing that
    could make it all simpler.)

 2) fix default podman path.

    When setting $PODMAN, default to the locally built
    one -- there may not be one in $PATH (e.g. in
    Ubuntu, see #6366). This in turn requires us to:

 3) run registry test in integration, not unit test

    It looks like unit tests run before podman is built,
    causing a chicken-egg dilemma. Try to solve that by
    running the new hack/podman-registry-go test in
    integration tests, not unit tests.

Signed-off-by: Ed Santiago <santiago@redhat.com>

hack/podman-registry

@@ -14,7 +14,7 @@ PODMAN_REGISTRY_PASS=
 PODMAN_REGISTRY_PORT=
 
 # Podman binary to run
-PODMAN=${PODMAN:-$(type -p podman)}
+PODMAN=${PODMAN:-$(dirname $0)/../bin/podman}
 
 # END   defaults
 ###############################################################################
@@ -176,11 +176,16 @@ function do_start() {
               -out ${AUTHDIR}/domain.crt                               \
               -subj "/C=US/ST=Foo/L=Bar/O=Red Hat, Inc./CN=localhost"
 
-    # Store credentials where container will see them
-    must_pass podman run --rm                                        \
-              --entrypoint htpasswd ${PODMAN_REGISTRY_IMAGE}         \
-              -Bbn ${PODMAN_REGISTRY_USER} ${PODMAN_REGISTRY_PASS}   \
-              > $AUTHDIR/htpasswd
+    # Store credentials where container will see them. We can't run
+    # this one via must_pass because we need its stdout.
+    podman run --rm                                               \
+           --entrypoint htpasswd ${PODMAN_REGISTRY_IMAGE}         \
+           -Bbn ${PODMAN_REGISTRY_USER} ${PODMAN_REGISTRY_PASS}   \
+           > $AUTHDIR/htpasswd
+    if [ $? -ne 0 ]; then
+        rm -rf ${PODMAN_REGISTRY_WORKDIR}
+        die "Command failed: podman run [htpasswd]"
+    fi
 
     # In case someone needs to debug
     echo "${PODMAN_REGISTRY_USER}:${PODMAN_REGISTRY_PASS}" \