conntrack-tools: adjust comment to match conditional

Commit 3afbc4f3 (conntrack-tools: uses dlopen(), not available on static
builds) adjusted the dependencies for the comment, but forgot to update the
comment itself.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/conntrack-tools/Config.in

@@ -16,7 +16,7 @@ config BR2_PACKAGE_CONNTRACK_TOOLS
 
 	  http://www.netfilter.org/projects/conntrack-tools/
 
-comment "conntrack-tools needs a toolchain w/ threads"
+comment "conntrack-tools needs a toolchain w/ threads, dynamic library"
 	depends on BR2_USE_MMU
 	depends on !(BR2_TOOLCHAIN_HAS_THREADS || BR2_TOOLCHAIN_HAS_NATIVE_RPC) || \
 		BR2_STATIC_LIBS