Reword the postgis unsupported information.

Author: Ashley Penney

README.md

@@ -869,12 +869,6 @@ If you have selinux enabled you must add any custom ports you use to the postgre
 # semanage port -a -t postgresql_port_t -p tcp $customport
 ```
 
-### RHEL7
-
-Currently the following features are unsupported:
-
-* Postgis (There is no existing postgis package for RHEL7, and it's not in EPEL7 yet.)
-
 Development
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