fix #116 allow backup directory with spaces

[Wikinaut]

@laurent22 here's a formal PR. Attention: I haven't tested it!

[laurent22]

It seems the pull request sometimes adds two pairs of double quotes, and sometimes one pair of double and one pair single quotes. For example:

"\'$DEST_FOLDER/\'"

"\"$INPROGRESS_FILE\""

That would result in:

"'my/path'"

""my/path""

Is there any reason for this?

Edit: Sorry just saw you haven't tested it, but obviously this needs to be tested as we don't want to break people's backup scripts.

[ventoh]

+1. For me that has solved the problem. ( directory with spaces in destination backup dir)