Remove identifier that causes warnings under OpenJDK 8 compiler

Bug: 24494019
Change-Id: Ifca3226d3de1c72cc24c6092e105b42b95408c18
diff --git a/src/java/com/google/android/mms/pdu/EncodedStringValue.java b/src/java/com/google/android/mms/pdu/EncodedStringValue.java
index 9495c1c..14ef772 100644
--- a/src/java/com/google/android/mms/pdu/EncodedStringValue.java
+++ b/src/java/com/google/android/mms/pdu/EncodedStringValue.java
@@ -145,7 +145,7 @@
             	}
             	try {
                     return new String(mData, CharacterSets.MIMENAME_ISO_8859_1);
-                } catch (UnsupportedEncodingException _) {
+                } catch (UnsupportedEncodingException e2) {
                     return new String(mData); // system default encoding.
                 }
             }
@@ -216,7 +216,7 @@
             try {
                 ret[i] = new EncodedStringValue(mCharacterSet,
                         temp[i].getBytes());
-            } catch (NullPointerException _) {
+            } catch (NullPointerException e) {
                 // Can't arrive here
                 return null;
             }