configs: tigher policy for firefox

configs/firefox-with-net.cfg

@@ -49,14 +49,8 @@ mount {
 }
 
 mount {
-	src: "/sbin"
-	dst: "/sbin"
-	is_bind: true
-}
-
-mount {
-	src: "/usr"
-	dst: "/usr"
+	src: "/usr/lib"
+	dst: "/usr/lib"
 	is_bind: true
 }
 
@@ -80,6 +74,12 @@ mount {
 	is_bind: true
 }
 
+mount {
+	src: "/usr/share"
+	dst: "/usr/share"
+	is_bind: true
+}
+
 mount {
 	src: "/dev/urandom"
 	dst: "/dev/urandom"
@@ -150,5 +150,5 @@ seccomp_string: "
 "
 
 exec_bin {
-        path: "/usr/bin/firefox"
+        path: "/usr/lib/firefox/firefox"
 }