Allow svn_error_init_pool() to be called more than once.
Allow svn_error_init_pool() to be called more than once.

Fix a bug: svn_boolean_t* is NOT compatible with a void**. The hash function
  would end up storing a void* into the svn_boolean_t variable. If there was
  a width or alignment problem, then this would break horribly.

(svn_error__get_error_pool): use temp void* variable for fetching values
  from the userdata.

(svn_error_init_pool): see if an error pool exists already, and bail if one
  has been found.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@839188 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion