Fix encodedWord regular expression(RFC 2047) to match quoted email addresses properly.

E.g of quoted email address: "From: \"=?ISO-8859-1?Q?=22Joh=F1_D=F6e=22?=\" <jdoe@example.net>"

Change-Id: I640fb127d640585099289558c6080cd1b698c331
Signed-off-by: Valerio Valerio <valerio.valerio@jollamobile.com>

Cherry-picked from upstream commit: 78c9582b11e9ea7f9e99bf0b89ee8db6cb276b12.