use correct string length

Change-Id: I2a5a0e496e80e1f5868e5ac09bfdba57a598ec90
Reviewed-on: https://gerrit.libreoffice.org/36271
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
diff --git a/tools/source/inet/inetmime.cxx b/tools/source/inet/inetmime.cxx
index 27f120a..27cb185 100644
--- a/tools/source/inet/inetmime.cxx
+++ b/tools/source/inet/inetmime.cxx
@@ -483,9 +483,7 @@ bool parseParameters(ParameterList const & rInput,
                eEncoding
                    = getCharsetEncoding(p->m_aCharset.getStr(),
                                                   p->m_aCharset.getStr()
                                                       + rInput.m_pList->
                                                             m_aCharset.
                                                                 getLength());
                                                       + p->m_aCharset.getLength());
            OUString aValue;
            bool bBadEncoding = false;
            Parameter * pNext = p;