Bug while editing a VNF/NS descriptor

	*Changed the content type to gzip in headers to support .gz files while editing VNF and NS
	descriptors.

Change-Id: I5126731d561fd2c9ca651e02c59a47a0daf6c472
Signed-off-by: Harshini Rajagopal <harshini.r@tataelxsi.co.in>