Wifi not working in Ubuntu 14.04.3

Since the wireless script result indicates you have Ubuntu 14.04.3 LTS

Distributor ID:  Ubuntu
Description:    Ubuntu 14.04.3 LTS
Release:    14.04
Codename:   trusty

This has been recently fixed upstream, follow the instructions to install the backported modules and needed firmware

sudo apt-get install build-essential linux-headers-$(uname -r) git
echo "options ath10k_core skip_otp=y" | sudo tee /etc/modprobe.d/ath10k_core.conf
wget https://www.kernel.org/pub/linux/kernel/projects/backports/2015/11/15/backports-20151115.tar.gz
tar zxvf backports-20151115.tar.gz
cd backports-20151115
make defconfig-wifi
make
sudo make install
git clone https://github.com/kvalo/ath10k-firmware.git
sudo cp -r ath10k-firmware/QCA9377 /lib/firmware/ath10k/
cp /lib/firmware/ath10k/QCA9377/hw1.0/firmware-5.bin_WLAN.TF.1.0-00267-1 /lib/firmware/ath10k/QCA9377/hw1.0/firmware-5.bin

And it should work after a reboot

If you have a kernel update and wireless quits again you will need to

cd backports-20151115
make clean
make defconfig-wifi
make
sudo make install