Fixed errors in the conditional operator "? :" parser.

test/err/bug1893.c

@@ -0,0 +1,8 @@
+/* bug #1893 - Compiler accepts a ternary expression where it shouldn't */
+
+int main(void)
+{
+    int a, b, c;
+    a == 1? b : c = 3;
+    return 0;
+}