create_gcov produces invalid output files

Hi,

I've download and built the autofdo project, however, when I do perf run and try to reformat the data using create_gcov the resulting files do not look correct. This is what I am seeing:

```
[sysprog@nucky ~] $ /usr/local/bin/create_gcov --binary=/usr/bin/lz_batch --profile=/tmp/profiling-data/prof20k-bir.raw -gcov_version 1 --gcov=/tmp/profiling-data/prof20k-bir.afdo
[sysprog@nucky ~] $ ls -ltr /tmp/profiling-data/prof20k-bir.*
-rwxrwxrwx 1 lzsystem lzsystem 1659536340 Apr 20 21:20 /tmp/profiling-data/prof20k-bir.raw
-rw-rw-r-- 1 sysprog sysprog 0 Apr 20 23:09 /tmp/profiling-data/prof20k-bir.afdo.imports
-rw-rw-r-- 1 sysprog sysprog 1600 Apr 20 23:09 /tmp/profiling-data/prof20k-bir.afdo
```

I have tried a number of profile data files but the result is always the same. The imports file is size 0 and the gcov file is 1600 bytes. The beginning of the file looks like the following:

```
0000000: 6164 6367 0100 0000 0000 0000 0000 00aa adcg............
0000010: 0300 0000 0100 0000 0100 0000 0000 0000 ................
0000020: 0000 00ac 0100 0000 0000 0000 0000 00ae ................
0000030: 0100 0000 0000 0000 0000 00af 8001 0000 ................
0000040: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0000050: 0000 0000 0000 0000 0000 0000 0000 0000 ................
0000060: 0000 0000 0000 0000 0000 0000 0000 0000 ................
```

The rest of the file is filled with all 0x0.