.ci: Modify shell scripts to two space indents

Give coala's shell scripts a standard.
Modify .sh files using `shfmt -i 2 -ci`
from https://github.com/mvdan/sh#shfmt.
This changes shell scripts according to
Google's guide.

Closes coala#2320

.ci/deps.sh

@@ -25,7 +25,7 @@ go get -u github.com/BurntSushi/toml/cmd/tomlv
 bundle install --path=vendor/bundle --binstubs=vendor/bin --jobs=8 --retry=3
 
 # Dart Lint commands
-if ! dartanalyzer -v &> /dev/null ; then
+if ! dartanalyzer -v &> /dev/null; then
   wget -nc -O ~/dart-sdk.zip https://storage.googleapis.com/dart-archive/channels/stable/release/1.14.2/sdk/dartsdk-linux-x64-release.zip
   unzip -n ~/dart-sdk.zip -d ~/
 fi

.ci/env_variables.sh

@@ -1,9 +1,9 @@
-export python_virtualenv=`pyenv prefix`
-export python_implementation=`python -c "import platform; print(platform.python_implementation())"`
-export python_version=`python -c "import sys; print(str(sys.version_info.major)+'.'+str(sys.version_info.minor))"`
+export python_virtualenv=$(pyenv prefix)
+export python_implementation=$(python -c "import platform; print(platform.python_implementation())")
+export python_version=$(python -c "import sys; print(str(sys.version_info.major)+'.'+str(sys.version_info.minor))")
 
-if [ "$(uname)" == "Darwin" ] ; then
+if [ "$(uname)" == "Darwin" ]; then
   export system_os="OSX"
-elif [ "$(expr substr $(uname -s) 1 5)" == "Linux" ] ; then
+elif [ "$(expr substr $(uname -s) 1 5)" == "Linux" ]; then
   export system_os="LINUX"
 fi

.ci/tests.sh

@@ -5,7 +5,7 @@ source .ci/env_variables.sh
 
 args=()
 
-if [ "$system_os" == "LINUX" ] ; then
+if [ "$system_os" == "LINUX" ]; then
   args+=('--cov' '--cov-fail-under=100' '--doctest-modules')
 fi