bug fix: local admins can edit profile fields of their users.

There has been a bug that allowed only global admins to modify or delete
profile fields of the users they are responsible for. This commit fixes
this behaviour. Local admins now can manage the profile fields of the
users they are responsible for.

uservoice tickets:
* no. 9: http://email.uservoice.com/c/ZD1kNTImaT01MzhmOTA5NDgzMmFjXzM5MDYzZjkxNmZlZGQzMWMyNDMzJTQwdXNlcnZvaWNlLmNvbSZoPTBmNDA5ZTNiZWQ5NjdmMDMxZWY0NjQxNTA2ZWM4NWU4Jmw9aHR0cCUzQSUyRiUyRndpbmdvbGYudXNlcnZvaWNlLmNvbSUyRmFkbWluJTJGdGlja2V0cyUyRjklM0ZlbWFpbF9sb2dpbl90b2tlbiUzRGExZWI3ZGVjMDdhY2RlMzZiZTM1NTA4YWRlN2E3YzYxJTI2dHJhY2tpbmdfY29kZSUzRDViNjllNjU3Zjk5YjhkMGYzYzdhNGYxYzY0NDNhNjRjJnRyYWNraW5nX2NvZGU9NWI2OWU2NTdmOTliOGQwZjNjN2E0ZjFjNjQ0M2E2NGMmcj1yZWljaGFyZHQuam9lcmclNDBnbWFpbC5jb20
* no. 10: http://email.uservoice.com/c/ZD1kNTImaT01Mzk2ZTZiMDExZWYxXzcxMmIzZmYwYTQxZTUzMTQ4MjU4YiU0MHVzZXJ2b2ljZS5jb20maD04NGVmYTc2MWZjYzFiZjY2NTFlZGRmM2FjYTNiZjU1MCZsPWh0dHAlM0ElMkYlMkZ3aW5nb2xmLnVzZXJ2b2ljZS5jb20lMkZhZG1pbiUyRnRpY2tldHMlMkYxMCUzRmVtYWlsX2xvZ2luX3Rva2VuJTNEYTFlYjdkZWMwN2FjZGUzNmJlMzU1MDhhZGU3YTdjNjElMjZ0cmFja2luZ19jb2RlJTNEZWRlOTMyYTZiZTc0ZDE5N2Y5ZmI4NmE0MmQ4NDQ0NWYmdHJhY2tpbmdfY29kZT1lZGU5MzJhNmJlNzRkMTk3ZjlmYjg2YTQyZDg0NDQ1ZiZyPXJlaWNoYXJkdC5qb2VyZyU0MGdtYWlsLmNvbQ