ycqlsh COPY TO/FROM round trip ESCAPE bug

[hstenzel]

Upstream cqlsh is able to round-trip csv files containing the \ character, ycqlsh with --debug led to corrupted data when the contents of the string contains \n. Every \n was transformed into \\n.

I'm using COPY $table TO/FROM STDOUT WITH HEADER = FALSE AND NULL = '<NULL>' AND ESCAPE = '\"';

Originally posted by @hstenzel in #3 (comment)