fix exception formatting

Author: gijzelaerr

cwltool/draft2tool.py

@@ -407,7 +407,7 @@ def collect_output_ports(self, ports, builder, outdir, compute_checksum=True):
                                 % shortname(port["id"]), exc_info=True)
                             raise WorkflowException(
                                 u"Error collecting output for parameter '%s':\n%s"
-                                % (shortname(port["id"]), indent(u(e))))
+                                % (shortname(port["id"]), indent(u(str(e)))))
 
             if ret:
                 adjustFileObjs(ret,

cwltool/expression.py

@@ -127,7 +127,7 @@ def next_seg(remain, obj):  # type: (Text, Any) -> Any
             try:
                 key = int(m.group(0)[1:-1])
             except ValueError as v:
-                raise WorkflowException(u(v))
+                raise WorkflowException(u(str(v)))
             if not isinstance(obj, list):
                 raise WorkflowException(" is a %s, cannot index on int '%s'" % (type(obj).__name__, key))
             if key >= len(obj):