Specified key was too long when use devstack to install cinder

[Eric Xie]

When i use devstack to install cinder, got error "Specified key was too long".

Log:
INFO migrate.versioning.api [-] 126 -> 127...
ERROR oslo_db.sqlalchemy.exc_filters [-] DBAPIError exception wrapped from (pymysql.err.InternalError) (1071, u'Specified key was too long; max key length is 767 bytes') [SQL: u'\nALTER TABLE quota_usages CHANGE COLUMN resource resource VARCHAR(300)'] (Background on this error at: http://sqlalche.me/e/2j85): InternalError: (1071, u'Specified key was too long; max key length is 767 bytes')
ERROR oslo_db.sqlalchemy.exc_filters Traceback (most recent call last):
ERROR oslo_db.sqlalchemy.exc_filters File "/usr/lib64/python2.7/site-packages/sqlalchemy/engine/base.py", line 1193, in _execute_context
ERROR oslo_db.sqlalchemy.exc_filters context)
ERROR oslo_db.sqlalchemy.exc_filters File "/usr/lib64/python2.7/site-packages/sqlalchemy/engine/default.py", line 509, in do_execute
ERROR oslo_db.sqlalchemy.exc_filters cursor.execute(statement, parameters)
ERROR oslo_db.sqlalchemy.exc_filters File "/usr/lib/python2.7/site-packages/pymysql/cursors.py", line 170, in execute
ERROR oslo_db.sqlalchemy.exc_filters result = self._query(query)
ERROR oslo_db.sqlalchemy.exc_filters File "/usr/lib/python2.7/site-packages/pymysql/cursors.py", line 328, in _query
ERROR oslo_db.sqlalchemy.exc_filters conn.query(q)
ERROR oslo_db.sqlalchemy.exc_filters File "/usr/lib/python2.7/site-packages/pymysql/connections.py", line 516, in query
ERROR oslo_db.sqlalchemy.exc_filters self._affected_rows = self._read_query_result(unbuffered=unbuffered)
ERROR oslo_db.sqlalchemy.exc_filters File "/usr/lib/python2.7/site-packages/pymysql/connections.py", line 727, in _read_query_result
ERROR oslo_db.sqlalchemy.exc_filters result.read()
ERROR oslo_db.sqlalchemy.exc_filters File "/usr/lib/python2.7/site-packages/pymysql/connections.py", line 1066, in read
ERROR oslo_db.sqlalchemy.exc_filters first_packet = self.connection._read_packet()
ERROR oslo_db.sqlalchemy.exc_filters File "/usr/lib/python2.7/site-packages/pymysql/connections.py", line 683, in _read_packet
ERROR oslo_db.sqlalchemy.exc_filters packet.check_error()
ERROR oslo_db.sqlalchemy.exc_filters File "/usr/lib/python2.7/site-packages/pymysql/protocol.py", line 220, in check_error
ERROR oslo_db.sqlalchemy.exc_filters err.raise_mysql_exception(self._data)
ERROR oslo_db.sqlalchemy.exc_filters File "/usr/lib/python2.7/site-packages/pymysql/err.py", line 109, in raise_mysql_exception
ERROR oslo_db.sqlalchemy.exc_filters raise errorclass(errno, errval)
ERROR oslo_db.sqlalchemy.exc_filters InternalError: (1071, u'Specified key was too long; max key length is 767 bytes')
ERROR oslo_db.sqlalchemy.exc_filters
Error during database migration: (pymysql.err.InternalError) (1071, u'Specified key was too long; max key length is 767 bytes') [SQL: u'\nALTER TABLE quota_usages CHANGE COLUMN resource resource VARCHAR(300)'] (Background on this error at: http://sqlalche.me/e/2j85)

Version of devstack
$ git log
commit 86011b700a89dc4e7e156eb662f435271934d5f1
Merge: 8fc227f 0ce6ae8
Author: Zuul <email address hidden>
Date: Sat Dec 15 10:24:47 2018 +0000

    Merge "Update cirros version"

[LIU Yulong (dragon889)]

Mark as duplicated since a former reported bug.