Don't encode the @ in addr-specs with rfc2047 if local-part contains

non-US-ASCII characters. This happens in anticipation of rfc2047 maybe becoming
allowed for local-parts (IDNA would be used for domain-names). Even if it's not,
this is still better than encoding the complete addr-spec (sans < > )

svn path=/trunk/kdenetwork/kmail/; revision=153614

kmmsgbase.cpp

@@ -464,7 +464,7 @@ QString KMMsgBase::decodeRFC2047String(const QCString& aStr)
 
 //-----------------------------------------------------------------------------
 const QString especials = "()<>@,;:\"/[]?.= \033";
-const QString dontQuote = "\"()<>,";
+const QString dontQuote = "\"()<>,@";
 
 QCString KMMsgBase::encodeRFC2047Quoted(const QCString& aStr, bool base64)
 {