scripted-diff: Rename PACKAGE_* variables to CLIENT_*

This change ensures consistent use of the `CLIENT_` namespace everywhere
in the repository.

-BEGIN VERIFY SCRIPT-

ren() { sed -i "s/\<$1\>/$2/g" $( git grep -l "$1" ./cmake ./src :\(exclude\)./src/secp256k1 ./test ) ; }

ren PACKAGE_NAME      CLIENT_NAME
ren PACKAGE_VERSION   CLIENT_VERSION_STRING
ren PACKAGE_URL       CLIENT_URL
ren PACKAGE_BUGREPORT CLIENT_BUGREPORT

-END VERIFY SCRIPT-

src/clientversion.cpp

@@ -36,7 +36,7 @@ const std::string UA_NAME("Satoshi");
     #define BUILD_DESC BUILD_GIT_TAG
     #define BUILD_SUFFIX ""
 #else
-    #define BUILD_DESC "v" PACKAGE_VERSION
+    #define BUILD_DESC "v" CLIENT_VERSION_STRING
     #if CLIENT_VERSION_IS_RELEASE
         #define BUILD_SUFFIX ""
     #elif defined(BUILD_GIT_COMMIT)
@@ -88,7 +88,7 @@ std::string LicenseInfo()
     return CopyrightHolders(strprintf(_("Copyright (C) %i-%i").translated, 2009, COPYRIGHT_YEAR) + " ") + "\n" +
            "\n" +
            strprintf(_("Please contribute if you find %s useful. "
-                       "Visit %s for further information about the software.").translated, PACKAGE_NAME, "<" PACKAGE_URL ">") +
+                       "Visit %s for further information about the software.").translated, CLIENT_NAME, "<" CLIENT_URL ">") +
            "\n" +
            strprintf(_("The source code is available from %s.").translated, URL_SOURCE_CODE) +
            "\n" +