Fix typo in Test Removal Procedure doc

This commit fixes some typos in the Tempest Test Removal Procedure
document. The document was introduced by just copying from the wiki page
to this repo[1]. So we didn't paying attention at that time.

[1] I5f2322a5de7b73252e0162165eeaec120ec94948

Change-Id: Ia3b4f255cc688ddd4007cf80753923cb18799b98
1 file changed