Fix bug where monkey always tries to run multiple scripts.

Change condition so MonkeySourceRandromScript is only triggered on multiple
scripts.
diff --git a/cmds/monkey/src/com/android/commands/monkey/Monkey.java b/cmds/monkey/src/com/android/commands/monkey/Monkey.java
index 4310323..bb0663f 100644
--- a/cmds/monkey/src/com/android/commands/monkey/Monkey.java
+++ b/cmds/monkey/src/com/android/commands/monkey/Monkey.java
@@ -407,7 +407,7 @@
             mEventSource.setVerbose(mVerbose);
 
             mCountEvents = false;
-        } else if (mScriptFileNames != null) {
+        } else if (mScriptFileNames != null && mScriptFileNames.size() > 1) {
             if (mSetupFileName != null) {
                 mEventSource = new MonkeySourceRandomScript(mSetupFileName, mScriptFileNames,
                         mThrottle, mSeed);