Use '[' insted of parens in thread name

Parentheses in the thread name messed up the display when viewing logs using
the colorcat.py tool. Instead, use square brackets.

Change-Id: I8e0053a7d90f828bd73bbabda8efce6110b5b69d
diff --git a/src/com/android/exchange/ExchangeService.java b/src/com/android/exchange/ExchangeService.java
index c719d0e..4a655a8 100644
--- a/src/com/android/exchange/ExchangeService.java
+++ b/src/com/android/exchange/ExchangeService.java
@@ -1618,7 +1618,7 @@
         synchronized (sSyncLock) {
             String mailboxName = m.mDisplayName;
             String accountName = service.mAccount.mDisplayName;
-            Thread thread = new Thread(service, mailboxName + "(" + accountName + ")");
+            Thread thread = new Thread(service, mailboxName + "[" + accountName + "]");
             log("Starting thread for " + mailboxName + " in account " + accountName);
             thread.start();
             mServiceMap.put(m.mId, service);