Follow-up to r1926882, fix a bad copy-paste.

git-svn-id: https://svn.apache.org/repos/asf/serf/trunk@1926917 13f79535-47bb-0310-9956-ffa450edef68

Author: dsahlberg-apache-org

README

@@ -68,7 +68,7 @@ to apu-1-config in $APU or $APU/bin/apu-1-config.
 OPENSSL should specify the root of the install (e.g., /opt/local). The
 includes will be found $OPENSSL/include/openssl and libraries at $OPENSSL/lib.
 
-OPENSSL should specify the root of the install. The includes will be found
+ZLIB should specify the root of the install. The includes will be found
 $ZLIB/include and libraries at $ZLIB/lib.
 
 The BROTLI and GSSAPI dependencies are optional.