Improved locale env vars safety during installation for postgresql

It was found that an LC_CTYPE=UTF-8 from iTerm2 on OSX was breaking the hub package install.

PostgreSQL docs suggest using 'C' locale unless otherwise needed
https://www.postgresql.org/docs/current/locale.html

> The drawback of using locales other than C or POSIX in PostgreSQL is its performance impact. It slows character handling and prevents ordinary indexes from being used by LIKE. For this reason use locales only if you actually need them.

Ticket: ENT-10739
Changelog: title

packaging/common/cfengine-hub/postinstall.sh

@@ -1,3 +1,4 @@
+export LC_ALL=C # force C locale as recommended by postgresql docs
 # (re)load SELinux policy if available and required before we start working with
 # our daemons and services below
 if [ `os_type` = "redhat" ] &&

packaging/common/cfengine-hub/preinstall.sh

@@ -1,3 +1,5 @@
+export LC_ALL=C # force C locale as recommended by postgresql docs
+
 
 if is_upgrade; then
     # This is nice to know to provide fixes for bugs in already released

packaging/common/script-templates/script-common.sh

@@ -3,6 +3,8 @@
 unset LANG
 unset LC_ADDRESS
 unset LC_ALL
+unset LC_CTYPE
+unset LC_COLLATE
 unset LC_IDENTIFICATION
 unset LC_MEASUREMENT
 unset LC_MONETARY