Rewind buffer with version string after using

Truncation flag checked in current position, but response buffer filled from the beginning, so we need rewind buffer

Author: artyom-smirnov

firebird/driver/core.py

@@ -1069,6 +1069,7 @@ def get_server_version(self, con: Union[Connection, Server]) -> str:
         else: # pragma: no cover
             # Unknown version
             result = '0.0.0.0'
+        self.response.rewind()
         self.con = None
         return result
     def get_engine_version(self, con: Union[Connection, Server]) -> float: