Fixed index out of bounds exception. This was causing msoy aux reporters to never complete if the report type was not registered on the game server (e.g. servlet ony)

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@5568 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/presents/server/ReportManager.java

@@ -21,9 +21,6 @@
 
 package com.threerings.presents.server;
 
-import java.util.List;
-
-import com.google.common.collect.Lists;
 import com.google.common.collect.Multimap;
 import com.google.common.collect.Multimaps;
 import com.google.inject.Singleton;
@@ -154,7 +151,7 @@ public class ReportManager
 
         // strip off the final newline
         int blen = report.length();
-        if (report.charAt(blen-1) == '\n') {
+        if (report.length() > 0 && report.charAt(blen-1) == '\n') {
             report.delete(blen-1, blen);
         }