Set LANG to en_US.UTF-8 for apt-cache policy

acloud will parse apt-cache policy result to check required package.
This is in case user's using different language for apt.

Bug: 135074015
Test: atest acloud_test &
sudo apt-get remove ssvnc &
acloud-dev create &
Check ssvnc will be installed during create process

Change-Id: I6271351b67d53c045dedfb76d6cbd1e04990cfdb
diff --git a/setup/setup_common.py b/setup/setup_common.py
index 497027e..06ee51e 100644
--- a/setup/setup_common.py
+++ b/setup/setup_common.py
@@ -25,7 +25,7 @@
 logger = logging.getLogger(__name__)
 
 PKG_INSTALL_CMD = "sudo apt-get --assume-yes install %s"
-APT_CHECK_CMD = "apt-cache policy %s"
+APT_CHECK_CMD = "LANG=en_US.UTF-8 apt-cache policy %s"
 _INSTALLED_RE = re.compile(r"(.*\s*Installed:)(?P<installed_ver>.*\s?)")
 _CANDIDATE_RE = re.compile(r"(.*\s*Candidate:)(?P<candidate_ver>.*\s?)")