Fix STARTTLS handshake error in Email's SmtpSender class

The Email.apk checks for "-STARTTLS" in the SMTP server's EHLO response
but SMTP servers may respond with STARTTLS on the last line as such:

250 STARTTLS

Or even as part of a line as such:

250-XSECURITY=NONE,STARTTLS

Checking for "-STARTTLS" in this case will break. The fix is to simply check
for "STARTTLS" instead.

See http://code.google.com/p/android/issues/detail?id=19109
And http://code.google.com/p/android/issues/detail?id=2309

Change-Id: I3a590a4398cb664f46875650550986a67f320f76

src/com/android/email/mail/transport/SmtpSender.java

@@ -136,7 +136,7 @@ public class SmtpSender extends Sender {
              * if not.
              */
             if (mTransport.canTryTlsSecurity()) {
-                if (result.contains("-STARTTLS")) {
+                if (result.contains("STARTTLS")) {
                     executeSimpleCommand("STARTTLS");
                     mTransport.reopenTls();
                     /*