run the whole spec dir by default, gate docker-backed specs on a variable

shellspec --tag ~integration filtered out untagged examples too, which
silently emptied the suite.

spec/spec_helper.sh

@@ -4,3 +4,8 @@ MYOS_ROOT=${MYOS_ROOT:-$SHELLSPEC_PROJECT_ROOT}
 SPEC_DIR=$MYOS_ROOT/spec
 export MYOS_ROOT SPEC_DIR
 . "$SPEC_DIR/support/run.sh"
+
+# Specs under spec/integration and spec/e2e drive a real docker daemon.
+# They are skipped unless MYOS_INTEGRATION=1 / MYOS_E2E=1 (make test-integration).
+myos_needs_docker() { [ -n "${MYOS_INTEGRATION:-}" ]; }
+myos_needs_swarm()  { [ -n "${MYOS_E2E:-}" ]; }