There's a closed pull request on the mblaze repository

Fix typo in reading body from arg
https://github.com/leahneukirchen/mblaze/pull/260

Description:
When given a body argument like this:

```
mcom foo@bar -body "this is my body"
```

the body isn't taken into account. This is because we try to `cat` from a file called "this is my body", instead of doing a process substitution for a file that fake-contains "this is my body". I believe it is a typo.