Fixed elvis expr parsing

Author: adamwojs

src/main/java/fr/adrienbrault/idea/symfony2plugin/expressionLanguage/ExpressionLanguage.bnf

@@ -84,7 +84,7 @@ expr ::= ternary_group
 private sign_group ::= unary_plus_expr | unary_min_expr
 private mul_group ::= mul_expr | div_expr | mod_expr
 private add_group ::= plus_expr | minus_expr
-private ternary_group ::= ternary_expr | elvis_expr
+private ternary_group ::= elvis_expr | ternary_expr
 
 private rel_group ::= identical_expr
     | eq_expr

src/test/java/fr/adrienbrault/idea/symfony2plugin/tests/expressionLanguage/testData/ElvisExpr.txt

@@ -1,12 +1,10 @@
 Expression Language File
-  ExpressionLanguageTernaryExprImpl(TERNARY_EXPR)
+  ExpressionLanguageElvisExprImpl(ELVIS_EXPR)
     ExpressionLanguageRefExprImpl(REF_EXPR)
       ExpressionLanguageIdentifierImpl(IDENTIFIER)
         PsiElement( ExpressionLanguageType.id)('a')
     PsiWhiteSpace(' ')
     PsiElement( ExpressionLanguageType.syntax)('?')
-    PsiErrorElement:<expr> expected, got ':'
-      <empty list>
     PsiElement( ExpressionLanguageType.syntax)(':')
     PsiWhiteSpace(' ')
     ExpressionLanguageRefExprImpl(REF_EXPR)