Bazel: Fix source jar fetching with provided classifier

If classifier is provided, then it should be stripped before appending
"-sources.jar" suffix for fetching sources artefact.

Bug: Issue 14154
Change-Id: Ic1886fa0887e532b1fbfae445500346a1e65b719
diff --git a/tools/bzl/maven_jar.bzl b/tools/bzl/maven_jar.bzl
index 15b1797..d96ffc2 100644
--- a/tools/bzl/maven_jar.bzl
+++ b/tools/bzl/maven_jar.bzl
@@ -60,7 +60,7 @@
     if len(parts) == 3:
         group_id, artifact_id, version = parts
     elif len(parts) == 4:
-        group_id, artifact_id, version, packaging = parts
+        group_id, artifact_id, version, classifier = parts
     elif len(parts) == 5:
         group_id, artifact_id, version, packaging, classifier = parts
     else:
@@ -158,7 +158,10 @@
     srcjar = None
     if ctx.attr.src_sha1 or ctx.attr.attach_source:
         srcjar = jar + "-src.jar"
-        srcurl = url + "-sources.jar"
+        srcurl = url
+        if coordinates.classifier != None:
+            srcurl = url.replace("-" + coordinates.classifier, "")
+        srcurl += "-sources.jar"
         srcjar_path = ctx.path("jar/" + srcjar)
         args = [python, script, "-o", srcjar_path, "-u", srcurl]
         if ctx.attr.src_sha1: