Bug 5795 [SIGNED-OFF] - Missing ReservesControlBranch system pref in database installer

Bug 5795 [SIGNED-OFF] - Missing ReservesControlBranch system pref in database installer

sysprefs.sql file was missing ReservesControlBranch.

To test:
1) Create a new installation and check sysprefs.sql loads correctly.
2) Check ReservesControlBranch shows up correctly in the sys pref editor.
3) Check sys pref can be edited and new value saves correctly.

Signed-off-by: Marc Veron <veron@veron.ch>
- Line is added at the end of installer/data/mysql/sysprefs.sql
- Tested Line diretly in MySQL with a systempreferences table where variable 'ReservesControlBranch' was missing. Data inserted correctly.
- Syspref shows up in Staff client

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
- Fixed merge conflict

Conflicts:

	installer/data/mysql/sysprefs.sql

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
- Tidied for 3.8.x