[bbb-greenlight] Use absolute path to the patch that should be removed

[Bartłomiej Piotrowski <bpiotrowski src gnome org>]

commit 756484ff3acd9c57d09953dd39ec5e8ebd39824e
Author: Bartłomiej Piotrowski <bpiotrowski gnome org>
Date:   Mon Jun 14 15:42:04 2021 +0200

    Use absolute path to the patch that should be removed

 Dockerfile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/Dockerfile b/Dockerfile
index 101738f..b264efa 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,4 +2,4 @@ FROM bigbluebutton/greenlight:v2
 ADD ldap.patch /ldap.patch
 RUN apk add -U patch && \
     patch -p1 -i /ldap.patch && \
-    rm -f ldap.patch
+    rm -f /ldap.patch