MLECO-2881: Using MD5 sum for downloaded resources check.

Removing git as a requirement for the checks performed for downloaded
resources. Another minor change is renaming of RTE_components.h to
RTE_Components.h as per the convention.

Change-Id: If93f80f2f5dfa6a3f143259904c33b3b6d3a6e7c
Signed-off-by: Kshitij Sisodia <kshitij.sisodia@arm.com>