SVNKit fails to upgrade source code, if there are any modified symlinks.

Reported in https://support.atlassian.com/browse/BSP-971 -

Many of our builds check out from subversion repositories that have symlinks in them, usually something like library.jar pointing to a file that is a specific version library-x.y.jar. An engineer may update the library by doing the following all in one commit:

svn rm library-1.2.jar
svn add library-1.3.jar
ln -sf library-1.3.jar library.jar
svn commit

SVNKit support confirmed this to be a bug, and said it would be fixed in 1.1.8 release. We need to upgrade to SVNKit 1.1.8 once released.