Revert "force redshfit decimals to int type"

This reverts commit 5343ff65.

pcigale/session/configuration.py

@@ -353,7 +353,7 @@ class Configuration(object):
             if self.config['data_file']:
                 obs_table = read_table(self.config['data_file'])
                 if 'redshift_decimals' in self.config['analysis_params']:
-                    decimals = int(self.config['analysis_params']['redshift_decimals'])
+                    decimals = self.config['analysis_params']['redshift_decimals']
                     if decimals < 0:
                         z = list(np.unique(obs_table['redshift']))
                     else: