shell: use f58 jobid encoding for shell service

Problem: The shell service name uses the decimal encoding of the
jobid as the suffix, but using the f58 encoding would make it more
clear that the service corresponds directly to a job.

Encode the jobid in the shell service name as f58.

Since the job-exec module builds the shell service topic string by
hand, update it as well.

Author: grondo

src/modules/job-exec/job-exec.c

@@ -174,9 +174,9 @@ flux_future_t *jobinfo_shell_rpc_pack (struct jobinfo *job,
     uint32_t rank;
 
     if (asprintf (&shell_topic,
-                  "%ju-shell-%ju.%s",
+                  "%ju-shell-%s.%s",
                   (uintmax_t) job->userid,
-                  (uintmax_t) job->id,
+                  idf58 (job->id),
                   topic) < 0
         || ((rank = resource_set_nth_rank (job->R, 0)) == IDSET_INVALID_ID))
         goto out;

src/shell/svc.c

@@ -35,6 +35,8 @@
 #include <unistd.h>
 #include <flux/core.h>
 
+#include "src/common/libjob/idf58.h"
+
 #include "internal.h"
 #include "task.h"
 #include "svc.h"
@@ -66,9 +68,9 @@ static int build_topic (struct shell_svc *svc,
 {
     if (snprintf (buf,
                   len,
-                  "%ju-shell-%ju%s%s",
+                  "%ju-shell-%s%s%s",
                   (uintmax_t)svc->uid,
-                  (uintmax_t)svc->shell->info->jobid,
+                  idf58 (svc->shell->info->jobid),
                   method ? "." : "",
                   method ? method : "") >= len) {
         errno = EINVAL;