r9410: fix case where reading a float which is already convert to a float by the backend
r9410: fix case where reading a float which is already convert to a float by the backend

sshirokov/CLSQL,ryszard/clsql,sshirokov/CLSQL,sshirokov/CLSQL,ryszard/clsql,ryszard/clsql,ryszard/clsql,intronic/clsql,sshirokov/CLSQL,intronic/clsql,intronic/clsql,intronic/clsql