Check for leading/trailing spaces in bundle specs

Warn the user when a leading or trailing space is found in one the
bundle specs they have configured using the Bundle command.

autoload/vundle/config.vim

@@ -24,6 +24,9 @@ func! vundle#config#require(bundles) abort
 endf
 
 func! vundle#config#init_bundle(name, opts)
+  if a:name != substitute(a:name, '^\s*\(.\{-}\)\s*$', '\1', '')
+    echo "Spurious leading and/or trailing whitespace found in bundle spec '" . a:name . "'"
+  endif
   let opts = extend(s:parse_options(a:opts), s:parse_name(substitute(a:name,"['".'"]\+','','g')))
   let b = extend(opts, copy(s:bundle))
   let b.rtpath = s:rtpath(opts)