Switch commoncpp2 to ucommon to solve dependency conflicts.

libccrtp was depending on commoncpp2, and have been replaced by a version
depending on ucommon as well.
diff --git a/jni/libzrtp/sources/zrtp/ZrtpPacketConfirm.cpp b/jni/libzrtp/sources/zrtp/ZrtpPacketConfirm.cpp
index 6f13cae..f558759 100644
--- a/jni/libzrtp/sources/zrtp/ZrtpPacketConfirm.cpp
+++ b/jni/libzrtp/sources/zrtp/ZrtpPacketConfirm.cpp
@@ -1,8 +1,8 @@
 /*
-  Copyright (C) 2006-2013 Werner Dittmann
+  Copyright (C) 2006-2007 Werner Dittmann
 
   This program is free software: you can redistribute it and/or modify
-  it under the terms of the GNU Lesser General Public License as published by
+  it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
@@ -66,17 +66,6 @@
     return true;
 }
 
-bool ZrtpPacketConfirm::isSignatureLengthOk() {
-    int32_t actualLen = getLength();
-    int32_t expectedLen = 19;                  // Confirm packet fixed part is 19 ZRTP words
-    int32_t sigLen = getSignatureLength();
-
-    if (sigLen > 0) {                          // We have a signature
-        expectedLen += sigLen + 1;             // +1 for the signature length field
-    }
-    return (expectedLen == actualLen);
-}
-
 int32_t ZrtpPacketConfirm::getSignatureLength() {
     int32_t sl = confirmHeader->sigLength & 0xff;
     if (confirmHeader->filler[1] == 1) {                              // do we have a 9th bit