Removes privilege modification for MYSQL_BASE_DIR

Reasons:
- No usage of the path MYSQL_BASE_DIR in the method.
- 2 Files used in the method are both in different locations
  /tmp/my.cnf.tmp and /etc/mysql/my.cnf
- It is just a hanging line of code without any reasons.

Changes:
- privilege modification line removed from code.

Change-Id: I676f7faaf1e7b78c5d0f9f79b622f230ae2b9740
Closes-Bug: #1261854
Merge "Removes privilege modification for MYSQL_BASE_DIR"