More random values for oAuth1 verifier

The oAuth1 verifier was generated as a random number ranging from
1000 to 9999. This small range of numbers is vulnerable to
brute-force attacks as described in CWE-330. The verifier is now
a 8-character long alphanumerical string, a good compromise between
security against guessing and ease of use.

SecurityImpact
Change-Id: Ibe4a2e57a02c261d85ba6c0d61696f134c54443e
Closes-Bug: #1236675
Ensure token is a string

Token is passed as a header from wsgi to HTTPD
If that token is unicode, it triggers an exception in mod_wsgi

Closes-Bug: 1312971

Change-Id: I4bb6ef6c98fbcd35435956d701f1ee3281e9935a
Merge "More random values for oAuth1 verifier"
Merge "Ensure token is a string"