Rename lwip library to lwip_legacy

Rename LwIP library in preparation for removal of LwIP libc plugin. The
current LwIP library will be replaced with a new version stripped of its
synchronous socket support. The next version will be incompatible with
the current, so removing 'lwip.lib.so' completely for a period makes it
easy to identify legacy users.

Fix #2797

repos/dde_linux/run/usb_net.run

@@ -93,7 +93,7 @@ install_config $config
 # generic modules
 set boot_modules {
 	core ld.lib.so init timer usb_drv
-	libc.lib.so vfs.lib.so libm.lib.so lwip.lib.so posix.lib.so test-lwip_httpsrv
+	libc.lib.so vfs.lib.so libm.lib.so lwip_legacy.lib.so posix.lib.so test-lwip_httpsrv
 }
 
 append_platform_drv_boot_modules

repos/dde_linux/run/usb_rndis.run

@@ -100,7 +100,7 @@ install_config $config
 # generic modules
 set boot_modules {
 	core ld.lib.so init timer usb_drv
-	libc.lib.so vfs.lib.so libc_pipe.lib.so lwip.lib.so pthread.lib.so
+	libc.lib.so vfs.lib.so libc_pipe.lib.so lwip_legacy.lib.so pthread.lib.so
 	tcp_terminal
 	test-terminal_echo
 }

repos/dde_linux/run/wifi.run

@@ -142,7 +142,7 @@ set boot_modules {
 	wifi.lib.so
 	wifi_drv
 
-	test-lwip_httpsrv lwip.lib.so
+	test-lwip_httpsrv lwip_legacy.lib.so
 }
 
 append boot_modules $firmware_modules