tests: Skip tests requiring trivial-httpd without it

I think we just got by with this because our unit tests
were always run in an environment that had it...

tests/libtest.sh

@@ -183,7 +183,7 @@ fi
 if test -z "${OSTREE_HTTPD:-}"; then
     OSTREE_HTTPD="${test_builddir}/ostree-trivial-httpd"
     if ! [ -x "${OSTREE_HTTPD}" ]; then
-        fatal "Failed to find ${OSTREE_HTTPD}"
+        OSTREE_HTTPD=
     fi
 fi
 

tests/test-admin-gpg.sh

@@ -21,6 +21,11 @@ set -euo pipefail
 
 . $(dirname $0)/libtest.sh
 
+if test -z "${OSTREE_HTTPD}"; then
+    echo "1..0 #SKIP no ostree-trivial-httpd"
+    exit 0
+fi
+
 setup_os_repository_signed () {
     mode=$1
     shift

tests/test-commit-sign.sh

@@ -26,6 +26,11 @@ if ! has_gpgme; then
     exit 0
 fi
 
+if test -z "${OSTREE_HTTPD}"; then
+    echo "1..0 #SKIP no ostree-trivial-httpd"
+    exit 0
+fi
+
 echo "1..7"
 
 keyid="472CDAFA"

tests/test-pull-contenturl.sh

@@ -21,6 +21,11 @@ set -euo pipefail
 
 . $(dirname $0)/libtest.sh
 
+if test -z "${OSTREE_HTTPD}"; then
+    echo "1..0 #SKIP no ostree-trivial-httpd"
+    exit 0
+fi
+
 echo "1..2"
 
 COMMIT_SIGN=""

tests/test-pull-metalink.sh

@@ -21,6 +21,11 @@ set -euo pipefail
 
 . $(dirname $0)/libtest.sh
 
+if test -z "${OSTREE_HTTPD}"; then
+    echo "1..0 #SKIP no ostree-trivial-httpd"
+    exit 0
+fi
+
 setup_fake_remote_repo1 "archive"
 
 echo '1..9'

tests/test-pull-mirrorlist.sh

@@ -21,6 +21,11 @@ set -euo pipefail
 
 . $(dirname $0)/libtest.sh
 
+if test -z "${OSTREE_HTTPD}"; then
+    echo "1..0 #SKIP no ostree-trivial-httpd"
+    exit 0
+fi
+
 echo "1..3"
 
 setup_fake_remote_repo1 "archive"

tests/test-pull-override-url.sh

@@ -21,6 +21,11 @@ set -euo pipefail
 
 . $(dirname $0)/libtest.sh
 
+if test -z "${OSTREE_HTTPD}"; then
+    echo "1..0 #SKIP no ostree-trivial-httpd"
+    exit 0
+fi
+
 setup_fake_remote_repo1 "archive"
 
 echo '1..1'