Adapt to reduced libu exposure in openwsman public api

Add a couple of #include "u/libu.h"
See commit 7d91f671 of openwsman
diff --git a/examples/create_resource.c b/examples/create_resource.c
index 52238e7..b66f289 100644
--- a/examples/create_resource.c
+++ b/examples/create_resource.c
@@ -41,7 +41,7 @@
 #include "wsman-xml-serializer.h"
 #include "wsman-client-api.h"
 #include "wsman-client-transport.h"
-
+#include "u/libu.h"
 
 #define RESOURCE_URI "http://example.com/wbem/wscim/1/schema/1/EXL_ExamplePolicy"
 #define CLASSNAME "EXL_ExamplePolicy"
diff --git a/examples/win32_service.c b/examples/win32_service.c
index 6c37ec7..1280ec6 100644
--- a/examples/win32_service.c
+++ b/examples/win32_service.c
@@ -40,6 +40,7 @@
 
 
 #include "wsman-api.h"
+#include "u/libu.h"
 
 #define RESOURCE_URI "http://schemas.microsoft.com/wbem/wsman/1/wmi/root/cimv2/Win32_Service"
 #define CLASSNAME "Win32_Service"
diff --git a/examples/wsmid_identify.c b/examples/wsmid_identify.c
index 78bcd48..094b082 100644
--- a/examples/wsmid_identify.c
+++ b/examples/wsmid_identify.c
@@ -40,6 +40,7 @@
 
 
 #include "wsman-api.h"
+#include "u/libu.h"
 
 struct __wsmid_identify
 {
diff --git a/src/wseventmgr.c b/src/wseventmgr.c
index 9eb4ae0..2a5131a 100644
--- a/src/wseventmgr.c
+++ b/src/wseventmgr.c
@@ -51,7 +51,7 @@
 #include <wsman-client-api.h>
 #include <wsman-client-transport.h>
 #include <wsman-debug.h>
-
+#include <u/libu.h>
 
 #if __linux__
 extern char *getpass (const char *__prompt);
diff --git a/src/wsman.c b/src/wsman.c
index 8a70481..693672e 100644
--- a/src/wsman.c
+++ b/src/wsman.c
@@ -51,7 +51,7 @@
 #include <wsman-client.h>
 #include <wsman-client-transport.h>
 #include <wsman-debug.h>
-
+#include <u/libu.h>
 
 #if __linux__
 extern char *getpass (const char *__prompt);