Fix gnc-numeric locale test on travis

- Change locale from de_DE to fr_FR.utf8
- Expect correct thousands separator

This also partly undoes the previous commit (it removes the
test for gcc 5 or more)

src/libqof/qof/gnc-numeric.hpp

@@ -350,13 +350,12 @@ std::basic_ostream<charT, traits>& operator<<(std::basic_ostream<charT, traits>&
     std::locale loc = s.getloc();
     ss.imbue(loc);
     char dec_pt = '.';
-#if __GNUC__ >= 5
     try
     {
         dec_pt = std::use_facet<std::numpunct<char>>(loc).decimal_point();
     }
     catch(const std::bad_cast& err) {} //Don't do anything, num_sep is already set.
-#endif
+
     ss.copyfmt(s);
     ss.width(0);
     if (n.denom() == 1)

src/libqof/qof/test/gtest-gnc-numeric.cpp

@@ -211,18 +211,16 @@ TEST(gncnumeric_stream, output_stream)
     GncNumeric rational_string(123, 456);
     output << rational_string;
     EXPECT_EQ("123/456", output.str());
-#if __GNUC__ >= 5
-    output.imbue(std::locale("de_DE"));
+    output.imbue(std::locale("fr_FR.utf8"));
     output.str("");
     output << simple_int;
-    EXPECT_EQ("123456", output.str());
+    EXPECT_EQ("123 456", output.str());
     output.str("");
     output << decimal_string;
     EXPECT_EQ("123,456", output.str());
     output.str("");
     output << rational_string;
     EXPECT_EQ("123/456", output.str());
-#endif
 }
 
 TEST(gncnumeric_stream, input_stream)