make PDOStatementWrapper return number of updated rows on INSERT, UPDATE or DELETE queries, introduces isManipulation() to guess type of query
fix numRows usage in user_ldap
fix numRows usage in core lib
fix numRows usage in files_encryption
use assertEquals number of rows in db tests
one if less
Merge pull request #3799 from owncloud/fix_pdo_statement_wrapper_numrows_on_modification

Fix pdo statement wrapper numrows on modification