[gnome-calculator] Constructors of abstract classes should not be public

[Rico Tzschichholz <ricotz src gnome org>]

commit 933de7789f7ccccd034eef4e80302b838379fab6
Author: Rico Tzschichholz <ricotz ubuntu com>
Date:   Mon Mar 18 10:04:12 2019 +0100

    Constructors of abstract classes should not be public

 lib/equation-parser.vala | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/lib/equation-parser.vala b/lib/equation-parser.vala
index 889b5d7f..8f0d954f 100644
--- a/lib/equation-parser.vala
+++ b/lib/equation-parser.vala
@@ -101,7 +101,7 @@ public class ParseNode : Object
 
 public abstract class RNode : ParseNode
 {
-    public RNode (Parser parser, LexerToken? token, uint precedence, Associativity associativity)
+    protected RNode (Parser parser, LexerToken? token, uint precedence, Associativity associativity)
     {
         base (parser, token, precedence, associativity);
     }
@@ -132,7 +132,7 @@ public abstract class RNode : ParseNode
 
 public abstract class LRNode : ParseNode
 {
-    public LRNode (Parser parser, LexerToken? token, uint precedence, Associativity associativity)
+    protected LRNode (Parser parser, LexerToken? token, uint precedence, Associativity associativity)
     {
         base (parser, token, precedence, associativity);
     }