Fix cosmetic problems in YAML source

This change corrects problems reported by the `yamllint` linter.

Since key duplication problems were removed in 4d48711, this commit
mainly fixes trailing spaces and extra empty lines at beginning/end of
files.

test/integration/targets/subversion/meta/main.yml

@@ -1,3 +1,2 @@
-dependencies: 
+dependencies:
   - prepare_tests
-

test/integration/targets/subversion/tasks/main.yml

@@ -116,4 +116,3 @@
       - "subverted4.changed"
 
 # TBA: test for additional options or URL variants welcome
-