install.sh: Fix bee registery of /etc/files

The function install_etc_files contains a bug which causes the files in
etc not to be probably registered in the crafted bee index of the
"mxtools-0.0-0" package.

The reason is, that the functions install_exe and install_data are
called from the last command of a pipeline. By default, this is executed
in a subshell, so the implicit modification of the global variable
INSTALLED_FILES is not seen by main process, which later uses it to
generate the index.

Make the loop run in the main shell process.

install.sh

@@ -103,13 +103,13 @@ function install_symlink()
 
 function install_etc_files()
 {
-    (cd etc ; find * -type f) | while read -r path; do
+    while read -r path; do
         if [[ -x etc/$path ]]; then
             install_exec etc/$path "$DESTDIR$sysconfdir/$path"
         else
             install_data etc/$path "$DESTDIR$sysconfdir/$path"
         fi
-    done
+    done < <(cd etc ; find * -type f)
 }
 
 function postinstall()