Merge branch 'jn/vcs-svn-cleanup' into maint

Code clean-up.

* jn/vcs-svn-cleanup:
vcs-svn: move remaining repo_tree functions to fast_export.h
vcs-svn: remove repo_delete wrapper function
vcs-svn: remove custom mode constants
vcs-svn: remove more unused prototypes and declarations

diff --cc Makefile
Simple merge

diff --cc vcs-svn/fast_export.c
Simple merge

diff --cc vcs-svn/fast_export.h
Simple merge

diff --cc vcs-svn/svndump.c
Simple merge