MDL-47975 assign: Stop gap fix for random time fails.
MDL-30968 mod/forum Fixed group link
MDL-47502 test_statslib_cron_daily: fix provider

Fiddling with the database in the data provider causes "out of sync"
errors when running suite tests.
MDL-39376 enrol: Optimized setting for ldap and database
MDL-48093 HTML 5 video: Firefox now supports .mp4
Merge branch 'MDL-48093-m27' of https://github.com/sammarshallou/moodle into MOODLE_27_STABLE
Merge branch 'MDL-47975-27' of git://github.com/damyon/moodle into MOODLE_27_STABLE
Merge branch 'MDL-47502' of https://github.com/eugeneventer/moodle-fixes into MOODLE_27_STABLE
MDL-47502 statslib tests: improve test

While integrating I noticed some problems which already existed in this
test:
* The enrolment data generator was not used
* The student roleid was hardocded
* The role assignment was at site level..
Merge branch 'MDL-30968-m27-forum-group-link' of https://github.com/amandadoughty/moodle into MOODLE_27_STABLE