Fixed invalid path in example showing how to remove element in layout xml.
Removed frontend/ directory from example which shows how to remove block in custom theme.
Merge branch 'fix_removing_elements' of https://github.com/wojtekn/devdocs into wojtekn-fix_removing_elements

Conflicts:
	guides/v1.0/frontend-dev-guide/layouts/xml-manage.md
Merge branch 'develop' of https://github.com/magento/devdocs into wojtekn-fix_removing_elements

Conflicts:
	guides/v1.0/frontend-dev-guide/layouts/xml-manage.md