Add directory remove on failed cloning

While downloading git repositories there was no removing
of created destination directory which could led to false
detection of downloaded repository.

This script adds directory remove in such case plus fixes
some minor typos in logging and help strings.

Issue-ID: OOM-1803

Change-Id: Iec672bc8248e7b2daee06717985e11f7e05aa5be
Signed-off-by: Milan Verespej <m.verespej@partner.samsung.com>
diff --git a/build/download/git_repos.py b/build/download/git_repos.py
index aff01b8..1d8c297 100755
--- a/build/download/git_repos.py
+++ b/build/download/git_repos.py
@@ -21,6 +21,7 @@
 
 import argparse
 import subprocess
+import shutil
 import logging
 import sys
 import os
@@ -63,18 +64,20 @@
             clone_repo(dst, *repo)
             progress.update(progress.value + 1)
         except subprocess.CalledProcessError as err:
+            if os.path.isdir(dst):
+                shutil.rmtree(dst)
             log.exception(err.output.decode())
             error_count += 1
 
     base.finish_progress(progress, error_count, log)
     if error_count > 0:
         log.error('{} were not downloaded. Check logs for details'.format(error_count))
-        raise RuntimeError('Download unsuccesfull')
+        raise RuntimeError('Download unsuccessful')
 
 def run_cli():
     parser = argparse.ArgumentParser(description='Download git repositories from list')
     parser.add_argument('git_list', metavar='git-list',
-                        help='File with list of npm packages to download.')
+                        help='File with list of git repos to download.')
     parser.add_argument('--output-dir', '-o', default=os.getcwd(),
                         help='Download destination')