fixup! Build ewk with gyp instead of cmake

fixup! Build ewk with gyp instead of cmake

Before [1], we use to build EWK from a separate repo
using CMake and unittests were disabled by default.
Once [1] landed, the EWK build was integrated to the
GYP build, but unittests target continued optional for both
mobile and TV builds. On desktop build though, no
targets were never specified to GYP, so all targets
including the unsopported unittests target, were being
build. This broke the desktop build.

[1] http://165.213.202.130:8080/#/c/70211/

Patch changes the build_desktop.sh script so that
the same targets are build for both desktop, tv and
mobile builds, being 'unittests' target optional.
By doing this, the desktop build is fixed.

Also, it rename build_ewk_test to build_ewk_tests in
packaging/chromium-efl.spec

Change-Id: Ibbe455ed411180f7b93c396512221c6cfdd5547c
Signed-off-by: Antonio Gomes <a1.gomes@samsung.com>