Avoid a theoretical case where we call editor->abort_edit() twice. (Only triggerable by an import, which imported nothing... where the first abort fails)
Found by: ivan
* subversion/libsvn_client/import.c (import_ctx_t): Remove TODO comment that describes implementation that doesn't follow current best practices. (import): Add output argument describing whether we committed something. Allocate import_ctx on the stack. Remove abort on no-change. (svn_client_import5): Use new information to determine when to abort. Always destroy iterpool.