Fix config var name to suppress version warnings

Also fix incorrect attribution of feature

doc/bufexplorer.txt

@@ -264,7 +264,7 @@ The default is 1.
 CHANGE LOG                                              *bufexplorer-changelog*
 
 7.4.20   January 18, 2017
-    - Thanks to arcseldon for supplying code that can remove the warning
+    - Thanks to jpflouret for supplying code that can remove the warning
       messages if you using this plugin on an older version of Vim.  The
       global variable is g:bufExplorerVersionWarn.
 7.4.19   September 18, 2017

plugin/bufexplorer.vim

@@ -95,7 +95,7 @@ endif
 if v:version > 703 || v:version == 703 && has('patch1261') && has('patch1264')
     " We are good to go.
 else
-    if g:bufexplorer_version_warn
+    if g:bufExplorerVersionWarn
         echohl WarningMsg
         echo "Sorry, bufexplorer ".g:bufexplorer_version." required Vim 7.3 or greater with patch1261 and patch1264."
         echohl None