gvisor/bazel: use python2 to build runsc-debian

$ bazel build runsc:runsc-debian
  File ".../bazel_tools/tools/build_defs/pkg/make_deb.py", line 311,
  in GetFlagValue:
    flagvalue = flagvalue.decode('utf-8')
AttributeError: 'str' object has no attribute 'decode'

make_deb.py is incompatible with Python3.
bazelbuild/bazel#8443

PiperOrigin-RevId: 253640180

runsc/BUILD

@@ -96,6 +96,11 @@ pkg_deb(
     maintainer = "The gVisor Authors <gvisor-dev@googlegroups.com>",
     package = "runsc",
     postinst = "debian/postinst.sh",
+    tags = [
+        # runsc-debian requires python2:
+        # /~https://github.com/bazelbuild/bazel/issues/8443
+        "manual",
+    ],
     version_file = ":version.txt",
     visibility = [
         "//visibility:public",

tools/run_tests.sh

@@ -90,6 +90,10 @@ build_everything() {
   bazel build \
     -c "${FLAVOR}" "${BAZEL_BUILD_RBE_FLAGS[@]}" \
     "${BUILD_PACKAGES[@]}"
+
+  # make_deb.py is incompatible with Python3.
+  # /~https://github.com/bazelbuild/bazel/issues/8443
+  bazel build --host_force_python=py2 runsc:runsc-debian
 }
 
 # Run simple tests runs the tests that require no special setup or