Some cleanup changes.

--
MOS_MIGRATED_REVID=87821306
diff --git a/src/main/java/com/google/devtools/build/lib/packages/RuleClass.java b/src/main/java/com/google/devtools/build/lib/packages/RuleClass.java
index b7da520..23f1c97 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/RuleClass.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/RuleClass.java
@@ -240,7 +240,7 @@
         @Override
         public void checkName(String name) {
           Preconditions.checkArgument(
-              (name.contains("$") && !TargetUtils.isTestRuleName(name)) || name.equals(""));
+              (name.contains("$") && !TargetUtils.isTestRuleName(name)) || name.isEmpty());
         }
 
         @Override
@@ -274,8 +274,9 @@
       NORMAL {
         @Override
         public void checkName(String name) {
-          Preconditions.checkArgument(!TargetUtils.isTestRuleName(name)
-              && RULE_NAME_PATTERN.matcher(name).matches(), "Invalid rule name: " + name);
+          Preconditions.checkArgument(
+              !TargetUtils.isTestRuleName(name) && RULE_NAME_PATTERN.matcher(name).matches(),
+              "Invalid rule name: %s", name);
         }
 
         @Override