Fix open empty file

src/jam

@@ -61,10 +61,10 @@ def read_cli():
             else:
                 openfile=arg
                 (ret,message)=filecheck.check_edit(openfile)
-                preread_conf(openfile)
                 if ret<0:
                     print(message,file=sys.stderr)
                     exit(-1)
+                preread_conf(openfile)
 
 # read command line arguments from configuration file
 def preread_conf(file):
@@ -72,8 +72,7 @@ def preread_conf(file):
     try:
         ff=open(file,"r")
     except:
-        print("error: could not read file '"+file+"' (this should not happen and is probably a bug)", file=sys.stderr)
-        exit(-1)
+        return
 
     # counter
     i=0