Fix NPE at com.android.internal.telephony.cdma.sms.BearerData.countAsciiSeptets

Check for empty text. Bug 4268602

Change-Id: I08dd567ad79a96ec92d4c418dd8e0f294ee66f4e
diff --git a/src/com/android/mms/data/WorkingMessage.java b/src/com/android/mms/data/WorkingMessage.java
index 47a6959..b70db7b 100755
--- a/src/com/android/mms/data/WorkingMessage.java
+++ b/src/com/android/mms/data/WorkingMessage.java
@@ -389,7 +389,7 @@
         }
 
         if (!MmsConfig.getMultipartSmsEnabled()) {
-            if (!append && mAttachmentType == TEXT) {
+            if (!append && mAttachmentType == TEXT && hasText()) {
                 int[] params = SmsMessage.calculateLength(getText(), false);
                 /* SmsMessage.calculateLength returns an int[4] with:
                 *   int[0] being the number of SMS's required,