Fixed PKGBUILD to correctly support custom package name

Without that if you try to specify custom name, you will get errors like 

```
==> Starting pkgver()...
/home/persienko/dev/tmp/makes/build/PKGBUILD: line 21: cd: /home/persienko/dev/tmp/makes/build/src/deployer: No such file or directory
==> Starting build()...
/home/persienko/dev/tmp/makes/build/PKGBUILD: line 26: cd: /home/persienko/dev/tmp/makes/build/src/deployer: No such file or directory
==> ERROR: A failure occurred in build().
    Aborting...
```