examples: remove all use of CURLM_CALL_MULTI_PERFORM

... since it is never returned since a long while back.
diff --git a/docs/examples/evhiperfifo.c b/docs/examples/evhiperfifo.c
index c2e87fc..e03801d 100644
--- a/docs/examples/evhiperfifo.c
+++ b/docs/examples/evhiperfifo.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -133,7 +133,6 @@
     const char *s;
     switch ( code )
     {
-    case CURLM_CALL_MULTI_PERFORM: s="CURLM_CALL_MULTI_PERFORM"; break;
     case CURLM_BAD_HANDLE:         s="CURLM_BAD_HANDLE";         break;
     case CURLM_BAD_EASY_HANDLE:    s="CURLM_BAD_EASY_HANDLE";    break;
     case CURLM_OUT_OF_MEMORY:      s="CURLM_OUT_OF_MEMORY";      break;
diff --git a/docs/examples/ghiper.c b/docs/examples/ghiper.c
index 9a3f46d..7571ffa 100644
--- a/docs/examples/ghiper.c
+++ b/docs/examples/ghiper.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -104,7 +104,6 @@
   if ( CURLM_OK != code ) {
     const char *s;
     switch (code) {
-      case     CURLM_CALL_MULTI_PERFORM: s="CURLM_CALL_MULTI_PERFORM"; break;
       case     CURLM_BAD_HANDLE:         s="CURLM_BAD_HANDLE";         break;
       case     CURLM_BAD_EASY_HANDLE:    s="CURLM_BAD_EASY_HANDLE";    break;
       case     CURLM_OUT_OF_MEMORY:      s="CURLM_OUT_OF_MEMORY";      break;
diff --git a/docs/examples/hiperfifo.c b/docs/examples/hiperfifo.c
index 4c4e223..84035aa 100644
--- a/docs/examples/hiperfifo.c
+++ b/docs/examples/hiperfifo.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -125,7 +125,6 @@
   if ( CURLM_OK != code ) {
     const char *s;
     switch (code) {
-      case     CURLM_CALL_MULTI_PERFORM: s="CURLM_CALL_MULTI_PERFORM"; break;
       case     CURLM_BAD_HANDLE:         s="CURLM_BAD_HANDLE";         break;
       case     CURLM_BAD_EASY_HANDLE:    s="CURLM_BAD_EASY_HANDLE";    break;
       case     CURLM_OUT_OF_MEMORY:      s="CURLM_OUT_OF_MEMORY";      break;