add new trimWhitespace() function

see: #2391
add tests for trimWhitespace()

see: #2391
trim whitespace from DMI information

see: #2391
trim whitespace from /proc information

closes: #2391
allow to pass files for testing

see: #2361
tests for new Megacli module

see: #2361
fix breakage introduced by commit #5a0d3cfa

closes: #2361
no need for a variable