Merge #11943: contrib: fix typo in install_db4.sh help message

ce552b6 contrib: fix typo in install_db4.sh help message (Wladimir J. van der Laan)

Pull request description:

  It installs db4, not db5.

Tree-SHA512: c503819bd46da1fc5bd386fbf7cab1702ed8a9f0532a5f9e81f8737dfc1c7883eddf54d7de78418f327e60627ed344f94b1c2819101971e0f170b2c4c0ba4efe

Author: laanwj

contrib/install_db4.sh

@@ -7,7 +7,7 @@ set -e
 if [ -z "${1}" ]; then
   echo "Usage: ./install_db4.sh <base-dir> [<extra-bdb-configure-flag> ...]"
   echo
-  echo "Must specify a single argument: the directory in which db5 will be built."
+  echo "Must specify a single argument: the directory in which db4 will be built."
   echo "This is probably \`pwd\` if you're at the root of the bitcoin repository."
   exit 1
 fi