Convert j2objc workspace name to use _, not -

We're restricted repository names in preparation for improving the runfiles
situation.

RELNOTES: j2objc tools can now be accessed via @bazel_j2objc, not @bazel-j2objc.

--
MOS_MIGRATED_REVID=113071304

src/main/java/com/google/devtools/build/lib/bazel/rules/objc/j2objc.WORKSPACE

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/objc/j2objc.WORKSPACE b/src/main/java/com/google/devtools/build/lib/bazel/rules/objc/j2objc.WORKSPACE
index 43f5b41..5f82100 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/objc/j2objc.WORKSPACE
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/objc/j2objc.WORKSPACE
@@ -1,7 +1,7 @@
 # External dependencies for the java_* rules.
 
 new_http_archive(
-    name = "bazel-j2objc",
+    name = "bazel_j2objc",
     url = "https://github.com/google/j2objc/releases/download/0.9.8.1/j2objc-0.9.8.1.zip",
     sha256 = "3edff65fbfaa0a99fdb36dad97059070ba09b77ace7753573771204395dd862b",
     build_file = __embedded_dir__ + "/embedded_tools/third_party/java/j2objc/BUILD.remote"

third_party/java/j2objc/BUILD

diff --git a/third_party/java/j2objc/BUILD b/third_party/java/j2objc/BUILD
index 552b549..fdeac8c 100644
--- a/third_party/java/j2objc/BUILD
+++ b/third_party/java/j2objc/BUILD
@@ -40,7 +40,7 @@
     sdk_frameworks = [
         "Security",
     ],
-    deps = ["@bazel-j2objc//:jre_emul_archive"],
+    deps = ["@bazel_j2objc//:jre_emul_archive"],
 )
 
 # Proto support is a work in progress.

tools/j2objc/BUILD

diff --git a/tools/j2objc/BUILD b/tools/j2objc/BUILD
index b4f3483..c948948 100644
--- a/tools/j2objc/BUILD
+++ b/tools/j2objc/BUILD
@@ -10,7 +10,7 @@
 java_binary(
     name = "j2objc",
     main_class = "com.google.devtools.j2objc.J2ObjC",
-    runtime_deps = ["@bazel-j2objc//:j2objc"],
+    runtime_deps = ["@bazel_j2objc//:j2objc"],
 )
 
 py_library(