setup.py: Fix egg_info build error updating mapping of package to source directory

This commit addresses the following error:

```
$ python setup.py egg_info
running egg_info
creating createrepo_c.egg-info
writing dependency_links to createrepo_c.egg-info/dependency_links.txt
writing top-level names to createrepo_c.egg-info/top_level.txt
writing createrepo_c.egg-info/PKG-INFO
writing manifest file 'createrepo_c.egg-info/SOURCES.txt'
error: package directory 'createrepo_c' does not exist
```

It also updates the CMake install rules to ensure the __init__.py file
and the python modules are installed in the appropriate package.

1 files changed, 1 insertions, 1 deletions

diff --git a/setup.py b/setup.py
index 4cd3cf2..29c570f 100644
--- a/setup.py
+++ b/setup.py
@@ -19,7 +19,7 @@ setup(
     python_requires=">=3.5",
     packages=['createrepo_c'],
     package_dir={
-        'createrepo_c': 'createrepo_c'
+        'createrepo_c': 'src/python'
     },
     cmake_args=['-DPYTHON_DESIRED:STRING=3', '-DBUILD_LIBCREATEREPO_C_SHARED:BOOL=OFF'],
     cmake_languages=['C'],