Add `patch` in Bazel container. (#101)

diff --git a/container/ubuntu16_04/builders/bazel/container.yaml b/container/ubuntu16_04/builders/bazel/container.yaml
index 1173d15..59a420d 100644
--- a/container/ubuntu16_04/builders/bazel/container.yaml
+++ b/container/ubuntu16_04/builders/bazel/container.yaml
@@ -9,6 +9,10 @@
   command: 'openssl'
   args: ['version']
   expectedOutput: ['OpenSSL .*']
+- name: 'check-patch'
+  command: 'patch'
+  args: ['--version']
+  expectedOutput: ['GNU patch .*']
 - name: 'check-unzip'
   command: 'unzip'
   expectedOutput: ['.*Usage: unzip .*']
@@ -18,6 +22,7 @@
   expectedOutput: ['.*This is Zip.*']
 
 
+
 metadataTest:
   env:
     - key: 'PATH'
diff --git a/container/ubuntu16_04/layers/bazel/BUILD b/container/ubuntu16_04/layers/bazel/BUILD
index 39452d5..98eda91 100644
--- a/container/ubuntu16_04/layers/bazel/BUILD
+++ b/container/ubuntu16_04/layers/bazel/BUILD
@@ -26,6 +26,7 @@
     base = "@ubuntu16_04//image",
     packages = [
         "g++",
+        "patch",
         "software-properties-common",
         "unzip",
         "zip",