changed to PHP7 and changed to different TLS_CACERT filename.

Dockerfile

@@ -1,6 +1,6 @@
 FROM alpine:latest
 
-RUN apk --no-cache add php5-apache2 phpldapadmin=1.2.3-r4
+RUN apk --no-cache add php7-apache2 phpldapadmin
 
 ENV LDAP_SERVER='ldaps:\/\/ldap.slurm.ch:636'
 ENV LDAPROOT=dc=slurm,dc=ch