Use /etc/release instead of /etc/os-release to get OS name on Solaris.

Need to submit upstream.

--- gnome-control-center-3.18.2/panels/info/cc-info-panel.c~	2015-07-20 03:08:50.000000000 +0000
+++ gnome-control-center-3.18.2/panels/info/cc-info-panel.c	2016-10-15 13:22:56.504195284 +0000
@@ -460,6 +460,23 @@ get_os_type (void)
 
        g_free (buffer);
     }
+#ifdef __sun
+  else if (g_file_get_contents ("/etc/release", &buffer, NULL, NULL))
+    {
+      char *start = buffer;
+      char *end = strchr (start, '\n');
+        
+      if (start != NULL && end != NULL)
+        {
+          name = g_strndup (start, end - start);
+          if (name != NULL)
+            {
+              g_strstrip(name);
+            }
+        }
+       g_free (buffer);
+    }
+#endif
 
   if (GLIB_SIZEOF_VOID_P == 8)
     bits = 64;