curl: Memory leak in CURLOPT_XOAUTH2_BEARER

Summary: Once a bearer token is set with CURLOPTXOAUTH2BEARER, each HTTP request done with the same handler leaks the token itself. Steps To Reproduce: Given the following code: c include int mainvoid curlglobalinitCURLGLOBALALL; CURL curl = curleasyinit; curleasysetoptcurl, CURLOPTHTTPAUTH,...