.travis.yml: updated Linux builds.
.travis.yml: updated Linux builds.

Corrected the Linux builds.

Signed-off-by: Cristi Iacob <d9a5ee38e079268f5921cacbe589f9990ad49a4f@analog.com>

analogdevicesinc/Pixelpulse2,analogdevicesinc/Pixelpulse2,analogdevicesinc/Pixelpulse2