Added color to the terminal log messages

This adds color to the warning, error, and fatal log messages, by changing the
colour codes in the terminal for the error level in the log message. This way
warning and errors stick out more from the regular messages, and helps identify
errors.

Changelog: Title

Signed-off-by: Ole Petter <ole.orhagen@northern.tech>
(cherry picked from commit d3df1c961c)

modules/log.sh

@@ -18,6 +18,14 @@
 # from sub-directories
 log_file="${PWD}/work/convert.log"
 
+
+# Add some colour to the log messages
+
+YELLOW='\033[1;33m' # Warning
+RED='\033[0;31m'    # Error
+IRED='\033[0;91m'   # Fatal Error
+NC='\033[0m'        # No Color
+
 # Log the given message at the given level.
 function log {
   local -r level="$1"
@@ -50,18 +58,18 @@ function log_info {
 # Log the given message at WARN level.
 function log_warn {
   local -r message="$1"
-  log "WARN" "$message"
+  log "${YELLOW}WARN${NC}" "$message"
 }
 
 # Log the given message at ERROR level.
 function log_error {
   local -r message="$1"
-  log "ERROR" "$message"
+  log "${RED}ERROR${NC}" "$message"
 }
 
 # Log the given message at FATAL level.
 function log_fatal {
   local -r message="$1"
-  log "FATAL" "$message"
+  log "${IRED}FATAL${NC}" "$message"
   exit 1
 }