namespaces: remove pid_ns and net_ns experimental status

The pid namespace is in the kernel since 2.6.27 and the net_ns since
2.6.29.  They are enabled in the distro by default and used by userspace
component.  They are mature enough to remove the 'experimental' label.
Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

init/Kconfig

@@ -766,21 +766,18 @@ config USER_NS
 	  If unsure, say N.
 
 config PID_NS
-	bool "PID Namespaces (EXPERIMENTAL)"
+	bool "PID Namespaces"
 	default n
-	depends on NAMESPACES && EXPERIMENTAL
+	depends on NAMESPACES
 	help
 	  Support process id namespaces.  This allows having multiple
 	  processes with the same pid as long as they are in different
 	  pid namespaces.  This is a building block of containers.
 
-	  Unless you want to work with an experimental feature
-	  say N here.
-
 config NET_NS
 	bool "Network namespace"
 	default n
-	depends on NAMESPACES && EXPERIMENTAL && NET
+	depends on NAMESPACES && NET
 	help
 	  Allow user space to create what appear to be multiple instances
 	  of the network stack.