Fix bash syntax

Author: BanzaiMan

bin/install-libsodium

@@ -21,7 +21,7 @@ make install
 popd
 
 # add the option in custom_configure_options
-if [[ $VERSION =~ ^master$ ]] || [[ "$(printf "7.4\n$VERSION" | sort -V | head -n1)" >= "7.4" ]]; then
+if [[ $VERSION =~ ^master$ ]] || [[ "$(printf "7.4\n$VERSION" | sort -V | head -n1)" > "7.3.9999999999" ]]; then
 	echo "--with-sodium=$LIBSODIUM_INSTALL_DIR" >> $TRAVIS_BUILD_DIR/custom_configure_options
 else
 	echo "--with-libsodium=$LIBSODIUM_INSTALL_DIR" >> $TRAVIS_BUILD_DIR/custom_configure_options