fix for #67255. define a default for "mail.content_disposition_type"

sr=bienvenu

mailnews/compose/src/nsMsgCompUtils.cpp

@@ -907,7 +907,9 @@ mime_generate_attachment_headers (const char *type, const char *encoding,
 		char *period = PL_strrchr(real_name, '.');
 		PRInt32 pref_content_disposition = 0;
 
-    prefs->GetIntPref("mail.content_disposition_type", &pref_content_disposition);
+        rv = prefs->GetIntPref("mail.content_disposition_type", &pref_content_disposition);
+        NS_ASSERTION(NS_SUCCEEDED(rv), "failed to get mail.content_disposition_type");
+
 		PUSH_STRING ("Content-Disposition: ");
 
 		if (pref_content_disposition == 1)

mailnews/mailnews.js

@@ -305,3 +305,4 @@ pref("mail.biff.play_sound",true);
 pref("mail.biff.use_default_sound",true);
 pref("mail.biff.sound_file","");
 
+pref("mail.content_disposition_type", 0);

modules/libpref/src/init/mailnews.js

@@ -305,3 +305,4 @@ pref("mail.biff.play_sound",true);
 pref("mail.biff.use_default_sound",true);
 pref("mail.biff.sound_file","");
 
+pref("mail.content_disposition_type", 0);