Fixed bugs in GWriteStream related to encoding of etag, anniversary and online
account

Signed-off-by: Sateesh Kavuri <sateesh@mobilitas.co>
Found two very weird bugs, one confirmed in Google and the other
possibly in Qt or Google. If a header key/value pair has a newline char,
then Google throws a "411" HTTP errors. This silly error literally took 2 days
of digging and finally figured that the auth token had a newline char
because of which POST requests were failing with a 411 error
(content-length required). Another Google bug (#3397) is that if
GDataVersion:3.0 is not the first header in the GET request, then the
data is not returned in 3.0 format.
While debugging these two issues, modified the GTransport mode, where
the transport object is created everytime, rather than being reused. In
the next commit, will go back to the reuse model of GTransport, instead
of re-creating it everytime.

Signed-off-by: Sateesh Kavuri <sateesh@mobilitas.co>