[chore] Make ShellCheck happy (#5484)

Cf. https://github.com/koreader/koreader/pull/5477#discussion_r334234063

platform/kobo/koreader.sh

@@ -258,9 +258,11 @@ while [ $RETURN_VALUE -ne 0 ]; do
         ./fbink -q -f -s top=0,left=0
         # Cue a lemming's faceplant sound effect!
 
-        echo "!!!!" >>crash.log 2>&1
-        echo "Uh oh, something went awry... (Crash n°${CRASH_COUNT}: $(date +'%x @ %X'))" >>crash.log 2>&1
-        echo "Running FW $(cut -f3 -d',' /mnt/onboard/.kobo/version) on Linux $(uname -r) ($(uname -v))" >>crash.log 2>&1
+        {
+            echo "!!!!"
+            echo "Uh oh, something went awry... (Crash n°${CRASH_COUNT}: $(date +'%x @ %X'))"
+            echo "Running FW $(cut -f3 -d',' /mnt/onboard/.kobo/version) on Linux $(uname -r) ($(uname -v))"
+        } >>crash.log 2>&1
         if [ $CRASH_COUNT -lt 5 ] && [ "${ALWAYS_ABORT}" = "false" ]; then
             echo "Attempting to restart KOReader . . ." >>crash.log 2>&1
             echo "!!!!" >>crash.log 2>&1