eina: fix for escapable charachters not getting escaped if it comes after '\t' or...

eina: fix for escapable charachters not getting escaped if it comes after '\t' or '\n'

Summary:
Escaping is not happening whenever any escapable characters is coming after
'\t' or '\n'. It will also fix invalid read of 1 byte which happens for string where
last charachter is '\t' or '\n' like "eina\t".

Test Plan:
Take a string like "eina\t ". Observe space which is followed by tab is not getting
escaped.

Signed-off-by: Prasoon Singh <prasoon.16@samsung.com>
Reviewers: shilpasingh, rajeshps, govi, cedric

Reviewed By: shilpasingh

Subscribers: cedric, jpeg

Differential Revision: https://phab.enlightenment.org/D4847

Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>
Change-Id: Ie2cd495024390b3fdb5dba81a660680d6b2fa9d1