Replaced the word components with component(s)

Current wording in exception messages of sahara
is misleading

Even when there is a single component, exceptions.py
and test_job_executor.py use the word "components"
instead of "component".

Observed exception message was "Hadoop cluster
should contain 1 oozie components.".
Instead, the exception message should be
"Hadoop cluster should contain 1 oozie component(s)."
to avoid confusion.

To avoid this confusion, the word "components" has
been replaced with the word "component(s)"

Closes-Bug : #1312908
Change-Id: I6f385a52669bc05fb0bf28cacaf88688576c10c5
Merge "Replaced the word components with component(s)"