Output errors from helper scripts to stderr (#156)

Author: elprans

integration/linux/find.sh

@@ -2,15 +2,15 @@
 # This script is needed for macOS support.
 
 if [[ $BASH_VERSION =~ ^[3] ]]; then
-    echo "Install a newer Bash version with 'brew install bash'"
+    echo "Install a newer Bash version with 'brew install bash'" >&2
     exit 1
 fi
 
 if which xcode-select >/dev/null 2>&1; then
 	# macOS
 	FIND="$(which gfind)"
 	if [[ ! -e $FIND ]]; then
-		echo "Install gnu-find with 'brew install findutils'"
+		echo "Install gnu-find with 'brew install findutils'" >&2
 		exit 1
 	fi
 else