Fix arping methods not handling whitespace

CONTRIBUTING.md

@@ -16,6 +16,7 @@ to bring new members into the community, and can always use the help.
 (cursing/swearing), NSFW text/content, or racism are NOT ok.
 
 ## Checklist before submitting a pull request
+* [ ] Code is formatted with Black: `black getmac tests`
 * [ ] All tests run and pass locally
     * [ ] `tox`
     * [ ] `tox -e check`

getmac/getmac.py

@@ -395,7 +395,7 @@ def _arping_habets(host):
     """Parse https://github.com/ThomasHabets/arping output."""
     return _search(
         r"^%s$" % MAC_RE_COLON,
-        _popen("arping", "-r -C 1 -c 1 %s" % host),
+        _popen("arping", "-r -C 1 -c 1 %s" % host).strip(),
     )
 
 
@@ -404,7 +404,7 @@ def _arping_iputils(host):
     """Parse iputils arping output."""
     return _search(
         r" from %s \[(%s)\]" % (re.escape(host), MAC_RE_COLON),
-        _popen("arping", "-f -c 1 %s" % host),
+        _popen("arping", "-f -c 1 %s" % host).strip(),
     )