patch 8.2.0138: memory leak when starting a job fails

Problem:    Memory leak when starting a job fails.
Solution:   Free the list of arguments. (Ozaki Kiichi, closes #5510)

src/channel.c

@@ -5818,9 +5818,9 @@ job_start(
     char_u	*cmd = NULL;
     char	**argv = NULL;
     int		argc = 0;
+    int		i;
 #if defined(UNIX)
 # define USE_ARGV
-    int		i;
 #else
     garray_T	ga;
 #endif
@@ -5994,7 +5994,11 @@ job_start(
     vim_free(ga.ga_data);
 #endif
     if (argv != job->jv_argv)
+    {
+	for (i = 0; argv[i] != NULL; i++)
+	    vim_free(argv[i]);
 	vim_free(argv);
+    }
     free_job_options(&opt);
     return job;
 }

src/testdir/test_channel.vim

@@ -1977,3 +1977,8 @@ func Test_zz_ch_log()
   call assert_match("%s%s", text[2])
   call delete('Xlog')
 endfunc
+
+func Test_job_start_fails()
+  " this was leaking memory
+  call assert_fails("call job_start([''])", "E474:")
+endfunc

src/version.c

@@ -742,6 +742,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    138,
 /**/
     137,
 /**/