Added ' -pbkdf2 -iter 10000 ' to openssl command

Added in order to avoid this warning message:

  *** WARNING : deprecated key derivation used.
  Using -iter or -pbkdf2 would be better.

Relevant:
 elasticdog#55
 https://askubuntu.com/questions/1093591/how-should-i-change-encryption-according-to-warning-deprecated-key-derivat

transcrypt

@@ -296,7 +296,7 @@ save_helper_scripts() {
 		    cipher=$(git config --get --local transcrypt.cipher)
 		    password=$(git config --get --local transcrypt.password)
 		    salt=$(openssl dgst -hmac "${filename}:${password}" -sha256 "$filename" | tr -d '\r\n' | tail -c 16)
-		    ENC_PASS=$password openssl enc -$cipher -md MD5 -pass env:ENC_PASS -e -a -S "$salt" -in "$tempfile"
+		    ENC_PASS=$password openssl enc -$cipher -md MD5 -pbkdf2 -iter 10000 -pass env:ENC_PASS -e -a -S "$salt" -in "$tempfile"
 		  fi
 		fi
 	EOF
@@ -307,7 +307,7 @@ save_helper_scripts() {
 		trap 'rm -f "$tempfile"' EXIT
 		cipher=$(git config --get --local transcrypt.cipher)
 		password=$(git config --get --local transcrypt.password)
-		tee "$tempfile" | ENC_PASS=$password openssl enc -$cipher -md MD5 -pass env:ENC_PASS -d -a 2>/dev/null || cat "$tempfile"
+		tee "$tempfile" | ENC_PASS=$password openssl enc -$cipher -md MD5 -pbkdf2 -iter 10000 -pass env:ENC_PASS -d -a 2>/dev/null || cat "$tempfile"
 	EOF
 
 	cat <<-'EOF' >"${GIT_DIR}/crypt/textconv"
@@ -317,7 +317,7 @@ save_helper_scripts() {
 		if [[ -s $filename ]]; then
 		  cipher=$(git config --get --local transcrypt.cipher)
 		  password=$(git config --get --local transcrypt.password)
-		  ENC_PASS=$password openssl enc -$cipher -md MD5 -pass env:ENC_PASS -d -a -in "$filename" 2>/dev/null || cat "$filename"
+		  ENC_PASS=$password openssl enc -$cipher -md MD5 -pbkdf2 -iter 10000 -pass env:ENC_PASS -d -a -in "$filename" 2>/dev/null || cat "$filename"
 		fi
 	EOF