Description of problem:
compress-device-out could support gzip/xz, but didn't support bzip2, reported as unsupported type, which is supported in el6, 
 
 ><fs> compress-device-out  bzip2 /dev/vda1 /tmp/compress_device
libguestfs: error: compress_device_out: compression type bzip2 is not supported
 
 checked the 1.6 branch, as following,

 daemon/compress.c, 
 136   else if (STREQ (ctype, "bzip2")) {
 137     CHECK_SUPPORTED ("bzip2");
 138     if (level == -1)
 139       snprintf (ret, n, "bzip2 -c");
 140     else if (level >= 1 && level <= 9)
 141       snprintf (ret, n, "bzip2 -c -%d", level);
 142     else {
 143       reply_with_error ("bzip2: incorrect value for level parameter");
 144       return -1;
 145     }
 146     return 0;
 
didn't find the api on 1.8 branch, 


Version-Release number of selected component (if applicable):
libguestfs-1.17.43-1.el7.x86_64


How reproducible:
always

Steps to Reproduce:
1.guestfish -N fs compress-device-out bzip2 /dev/vda1 compress
2.
3.
  
Actual results:
didn't support bzip2 for compress out 

Expected results:


Additional info: