correct off by one bug in setting up buffers for compression

git-svn-id: https://svn.mcs.anl.gov/repos/darshan/trunk@300 3b7491f3-a168-0410-bf4b-c445ed680a29

lib/darshan-mpi-io.c

@@ -1813,8 +1813,7 @@ static char* darshan_get_exe_and_mounts(struct darshan_job_runtime* final_job)
         NULL
     };
 
-    /* extra byte for \0 already accounted for */
-    space_left = CP_EXE_LEN;
+    space_left = CP_EXE_LEN + 1;
     trailing_data = malloc(space_left);
     if(!trailing_data)
     {