Enforce build with Java 11 for all by default

- Build with JDK11 and language levels (source and target) are now
enforced in .bazelrc, which depends on our own Java toolchain (defined
in tools/build/bazel/BUILD)
- Easymock bumped to v4.0.2 with support for Java 11 (minor API changes)
- The minimum required Bazel version is now 0.27.*

Change-Id: I0bb6dfe7fc1ea134b5a53dd249c369d58259688c
diff --git a/tools/build/bazel/generate_workspace.bzl b/tools/build/bazel/generate_workspace.bzl
index c177993..086ebea 100644
--- a/tools/build/bazel/generate_workspace.bzl
+++ b/tools/build/bazel/generate_workspace.bzl
@@ -1,4 +1,4 @@
-# ***** This file was auto-generated at Wed, 29 May 2019 22:17:30 GMT. Do not edit this file manually. *****
+# ***** This file was auto-generated at Mon, 17 Jun 2019 19:13:01 GMT. Do not edit this file manually. *****
 # ***** Use onos-lib-gen *****
 
 load("//tools/build/bazel:variables.bzl", "ONOS_GROUP_ID", "ONOS_VERSION")
@@ -295,9 +295,9 @@
     if "easymock" not in native.existing_rules():
         java_import_external(
             name = "easymock",
-            jar_sha256 = "0557c9fa845c951bdbe3940b605346a212172c64328277428297ef1fc6308e8f",
+            jar_sha256 = "104370107ef64d115e642cbdc14cea438a8d076f5aee9a9cb7882dc9a8ed4123",
             licenses = ["notice"],
-            jar_urls = ["http://repo1.maven.org/maven2/org/easymock/easymock/3.6/easymock-3.6.jar"],        )
+            jar_urls = ["http://repo1.maven.org/maven2/org/easymock/easymock/4.0.2/easymock-4.0.2.jar"],        )
     if "antlr" not in native.existing_rules():
         java_import_external(
             name = "antlr",
@@ -1353,7 +1353,7 @@
 artifact_map["@commons_pool//:commons_pool"] = "mvn:commons-pool:commons-pool:jar:1.6"
 artifact_map["@commons_text//:commons_text"] = "mvn:org.apache.commons:commons-text:jar:1.3"
 artifact_map["@concurrent_trees//:concurrent_trees"] = "mvn:com.googlecode.concurrent-trees:concurrent-trees:jar:2.6.1"
-artifact_map["@easymock//:easymock"] = "mvn:org.easymock:easymock:jar:3.6"
+artifact_map["@easymock//:easymock"] = "mvn:org.easymock:easymock:jar:4.0.2"
 artifact_map["@antlr//:antlr"] = "mvn:antlr:antlr:jar:NON-OSGI:2.7.7"
 artifact_map["@ganymed_ssh2//:ganymed_ssh2"] = "mvn:ch.ethz.ganymed:ganymed-ssh2:jar:NON-OSGI:262"
 artifact_map["@gmetric4j//:gmetric4j"] = "mvn:info.ganglia.gmetric4j:gmetric4j:jar:1.0.10"