Remove unnecessary special cases for bash/zsh (#2086)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

src/virtualenv/activation/bash/activate.sh

@@ -23,12 +23,10 @@ deactivate () {
         unset _OLD_VIRTUAL_PYTHONHOME
     fi
 
-    # This should detect bash and zsh, which have a hash command that must
-    # be called to get it to forget past commands.  Without forgetting
-    # past commands the $PATH changes we made may not be respected
-    if [ -n "${BASH-}" ] || [ -n "${ZSH_VERSION-}" ] ; then
-        hash -r 2>/dev/null
-    fi
+    # The hash command must be called to get it to forget past
+    # commands. Without forgetting past commands the $PATH changes
+    # we made may not be respected
+    hash -r 2>/dev/null
 
     if ! [ -z "${_OLD_VIRTUAL_PS1+_}" ] ; then
         PS1="$_OLD_VIRTUAL_PS1"
@@ -79,9 +77,7 @@ pydoc () {
     python -m pydoc "$@"
 }
 
-# This should detect bash and zsh, which have a hash command that must
-# be called to get it to forget past commands.  Without forgetting
-# past commands the $PATH changes we made may not be respected
-if [ -n "${BASH-}" ] || [ -n "${ZSH_VERSION-}" ] ; then
-    hash -r 2>/dev/null
-fi
+# The hash command must be called to get it to forget past
+# commands. Without forgetting past commands the $PATH changes
+# we made may not be respected
+hash -r 2>/dev/null