When testing all of the push functionality I ran into the fact that the
FTP upload code did not recognize that I had VAGRANT_CWD set, so it
wasn't finding the right files to upload.
This should make everything work properly relative to that location.
When the configured directory for FTP push has too many files, it will
generate an exception and fail due to a stack overflow. When this happens
just rescue out the exception and re-raise a custom error to provide
some context to the user on the actual problem.
Overcomes exception Net::SFTP::StatusException (2, "no such file") when using: "vagrant push" via sftp and a file parent directory does not exist. Function "upload" does not create the directory before uploading a file ('mkdir: true' seems to have no effect as zero directories are created while files are uploaded normally).
