a minor bug fix: check the iss state before trying to use it

git-svn-id: svn://bind10.isc.org/svn/bind10/trunk@791 e5f2f494-b856-4b98-b285-d166d9295462

src/lib/dns/cpp/rdata/generic/soa_6.cc

@@ -51,10 +51,10 @@ SOA::SOA(const string& soastr) :
     }
     mname_ = Name(token);
     iss >> token;
-    rname_ = Name(token);
     if (iss.bad() || iss.fail()) {
         dns_throw(InvalidRdataText, "Invalid SOA RNAME");
     }
+    rname_ = Name(token);
 
     uint32_t serial, refresh, retry, expire, minimum;
     iss >> serial >> refresh >> retry >> expire >> minimum;