travis-ci: updated ftp.pcre.org to sourceforge mirror to download pcre. (#784)

.travis.yml

@@ -123,7 +123,7 @@ jobs:
 
 install:
   - sudo cpanm --notest Test::Nginx IPC::Run3 > build.log 2>&1 || (cat build.log && exit 1)
-  - if [ ! -f download-cache/pcre-$PCRE_VER.tar.gz ]; then wget -P download-cache https://ftp.pcre.org/pub/pcre/pcre-$PCRE_VER.tar.gz; fi
+  - if [ ! -f download-cache/pcre-$PCRE_VER.tar.gz ]; then wget -P download-cache https://downloads.sourceforge.net/project/pcre/pcre/${PCRE_VER}/pcre-${PCRE_VER}.tar.gz; fi
   - if [ ! -f download-cache/openssl-$OPENSSL_VER.tar.gz ]; then wget -P download-cache https://www.openssl.org/source/openssl-$OPENSSL_VER.tar.gz || wget -P download-cache https://www.openssl.org/source/old/${OPENSSL_VER//[a-z]/}/openssl-$OPENSSL_VER.tar.gz; fi
   - tar zxf download-cache/pcre-$PCRE_VER.tar.gz
   - cd pcre-$PCRE_VER/