Make the webview_licenses.py step's name in Android bot more clear.

Review URL: https://codereview.chromium.org/1036513008

Cr-Commit-Position: refs/heads/master@{#322421}

testing/buildbot/chromium.linux.json

@@ -577,7 +577,7 @@
   "Android Tests (dbg)": {
     "scripts": [
       {
-        "name": "check_licenses",
+        "name": "webview_licenses",
         "script": "webview_licenses.py"
       }
     ]
@@ -585,7 +585,7 @@
   "Android Tests": {
     "scripts": [
       {
-        "name": "check_licenses",
+        "name": "webview_licenses",
         "script": "webview_licenses.py"
       }
     ]