Flux procmgr prints incorrect error message

[SamHerts]

Bug:

init_readymsg prints -1 as an error message instead of the desired pipe error message

Spindle/src/flux/procmgr.c

Lines 97 to 102 in 585dacf

	result = pipe(ready_pipe);
	if (result == -1) {
	error = result;
	fprintf(stderr, "Could not create ready pipe for spindle session: %s\n", strerror(error));
	return -1;
	}

Fix:

 result = pipe(ready_pipe); 
 if (result == -1) { 
    error = errno;