support MODE env to have spaces

[marc-portier]

This fix --> bb0afbf

introduced this line

mu-python-template/start.sh

Line 3 in 2ea41ed

if [ ${MODE:-""} == "development" ]; then

most likely to prevent the warning

unset MODE
/start.sh
./start-bad.sh: line 4: [: =: unary operator expected

because when MODE is unset the old approach lead the sh parser to trip over the test-syntax becoming [ = "development"] rather then [ "" = "development" ]

The more natural / elegant / simple / common strategy to this problem however is to simply use:

if [ "${MODE}" == "development" ]; then 

This has the added benefit of even supporting MODE values that have spaces in them. Cause in the current setup one would still have the sh parser trip over a use case like

export MODE="my mode"
/start.sh
./start-rpio.sh: line 4: [: too many arguments

simply because the test-syntax ends up as [ my mode = "development" ] rather then the hoped for [ "my mode" = "development" ]

I understand having MODE values with spaces is pushing beyond normal expectations, but as said, the suggested fix is also the more readable and common way of doing things.