fixup travis (failure to find preferences is not reported as error)

src/filesystem.cpp

@@ -703,23 +703,28 @@ static std::string read_stream(std::istream& s)
 	return ss.str();
 }
 
-std::istream *istream_file(const std::string &fname)
+std::istream *istream_file(const std::string &fname, bool treat_failure_as_error)
 {
-	LOG_FS << "Streaming " << fname << " for reading.\n";
+	LOG_FS << "Streaming " << fname << " for reading." << std::endl;
 	if (fname.empty())
 	{
-		ERR_FS << "Trying to open file with empty name.\n";
+		ERR_FS << "Trying to open file with empty name." << std::endl;
 		std::ifstream *s = new std::ifstream();
 		s->clear(std::ios_base::failbit);
 		return s;
 	}
 
 	std::ifstream *s = new std::ifstream(fname.c_str(),std::ios_base::binary);
-	if (s->is_open())
+	if (s->is_open()) {
 		return s;
-	ERR_FS << "Could not open '" << fname << "' for reading.\n";
-	return s;
+	}
 
+	if (treat_failure_as_error) {
+		ERR_FS << "Could not open '" << fname << "' for reading." << std::endl;
+	} else {
+		LOG_FS << "Could not open '" << fname << "' for reading." << std::endl;
+	}
+	return s;
 }
 
 std::string read_file(const std::string &fname)

src/filesystem.hpp

@@ -96,7 +96,7 @@ bool looks_like_pbl(const std::string& file);
  * to the game path (true) or to the current directory from which Wesnoth was run (false).
  */
 std::string read_file(const std::string &fname);
-std::istream *istream_file(const std::string &fname);
+std::istream *istream_file(const std::string &fname, bool treat_failure_as_error = true);
 std::ostream *ostream_file(std::string const &fname);
 /** Throws io_exception if an error occurs. */
 void write_file(const std::string& fname, const std::string& data);

src/preferences.cpp

@@ -60,7 +60,7 @@ base_manager::base_manager()
 {
 	try{
 #ifdef DEFAULT_PREFS_PATH
-		scoped_istream stream = istream_file(get_default_prefs_file());
+		scoped_istream stream = istream_file(get_default_prefs_file(),false);
 		read(prefs, *stream);
 
 		config user_prefs;
@@ -69,13 +69,13 @@ base_manager::base_manager()
 
 		prefs.merge_with(user_prefs);
 #else
-		scoped_istream stream = istream_file(get_prefs_file());
+		scoped_istream stream = istream_file(get_prefs_file(),false);
 		read(prefs, *stream);
 #endif
 	} catch(const config::error& e) {
 		ERR_CFG << "Error loading preference, message: "
 				<< e.what()
-				<< '\n';
+				<< std::endl;
 	}
 }