[WIP] Test properly, when multiple cookbooks are modified.

When multiple cookbooks are modified,
the current task does not test any one of the cookbooks,
because of the argument of the `split` function.

When specifying line-space, the argument should be surrounded by " now '.
Test properly, when multiple cookbooks are modified.

When multiple cookbooks are modified,
the current task does not test any one of the cookbooks,
because of the argument of the `split` function.

When specifying line-space, the argument should be surrounded by " not '.

```
diff --git a/tasks/tests/ci.rake b/tasks/tests/ci.rake
index 931d7e7..5f69eda 100755
--- a/tasks/tests/ci.rake
+++ b/tasks/tests/ci.rake
@@ -6,7 +6,7 @@ desc "Run CI tests."
 task :test do
   cookbooks = `git diff --name-only master..$(git symbolic-ref HEAD) | grep site-cookbooks | cut -f 2 -d / | awk '!a[$0]++'`

-  cookbooks.split('\n').each do |cookbook|
+  cookbooks.split("\n").each do |cookbook|
     cookbook.strip!

     cd "site-cookbooks/#{cookbook}/" do
```
Merge pull request #161 from kazu634/hotfix-for-test-task

Test properly, when multiple cookbooks are modified.
[wordpress] Do not run tests when `wordpress` cookbook is modified.

```
diff --git a/tasks/tests/build-images.rake b/tasks/tests/build-images.rake
index 38126c4..44d9f76 100755
--- a/tasks/tests/build-images.rake
+++ b/tasks/tests/build-images.rake
@@ -5,7 +5,7 @@ require 'rake'
 desc "Build docker images"
 task :build do
   # Retrieve the list of the modified files:
-  modified_files = `git diff --name-only master..\`git symbolic-ref HEAD\``
+  modified_files = `git diff --name-only master..\`git symbolic-ref HEAD\` | grep -v wordpress`

   # If no cookbooks are modified, exit task:
   unless modified_files.include?("site-cookbooks")
```