Update ICU to 58.1

source/i18n/umsg.cpp

Index: source/i18n/umsg.cpp
diff --git a/source/i18n/umsg.cpp b/source/i18n/umsg.cpp
index 8143932e7ef13cb4d6558824a23d7e86ae7c2989..179ab84e5481e034011cff2e258d3de10d2baf62 100644
--- a/source/i18n/umsg.cpp
+++ b/source/i18n/umsg.cpp
@@ -1,3 +1,5 @@
+// Copyright (C) 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
 /*
 *******************************************************************************
 *
@@ -469,7 +471,7 @@ umsg_vformat(   const UMessageFormat *fmt,
         }
     }
     UnicodeString resultStr;
-    FieldPosition fieldPosition(0);
+    FieldPosition fieldPosition(FieldPosition::DONT_CARE);
     
     /* format the message */
     ((const MessageFormat*)fmt)->format(args,count,resultStr,fieldPosition,*status);