Bazel: Fix more buildifier warnings

This fixes buildifier warnings that were not fixed in automatic
mode:

  $ find . \( -name BUILD -o -name "*.bzl" \) -print \
      | xargs buildifier --lint=warn

* Remove unused variables
* Pattern `src/test/java/com/google/gerrit/server/project/Util.java`
  has no wildcard ('*')
* All calls to rules or macros should pass arguments by keyword
  (arg_name=value) syntax
* ctx.new_file is deprecated, used ctx.actions.declare_file instead

Change-Id: I1f8a04e8d576ab637ba8a46118720218ec486fff

gerrit-plugin-api/BUILD

@@ -1,11 +1,5 @@
 load("//tools/bzl:javadoc.bzl", "java_doc")
 
-SRCS = [
-    "gerrit-server/src/main/java/",
-    "gerrit-httpd/src/main/java/",
-    "gerrit-sshd/src/main/java/",
-]
-
 PLUGIN_API = [
     "//gerrit-httpd:httpd",
     "//gerrit-pgm:init-api",