Fix Ant web.dir property casing

[tlamb96]

The ant compile command fails on Debian 10 due to the web.dir property casing.

$ ant compile
Buildfile: /home/admin/CoverageWebApplication/build.xml

init:

compile:
    [mkdir] Created dir: /home/admin/CoverageWebApplication/webcontent/WEB-INF/classes
     [echo]  Compiling coverage source in src into webcontent/WEB-INF/classes
    [javac] /home/admin/CoverageWebApplication/build.xml:62: warning: 'includeantruntime' was not set, defaulting to build.sysclasspath=last; set to false for repeatable builds
    [javac] Compiling 37 source files to /home/admin/CoverageWebApplication/webcontent/WEB-INF/classes

BUILD FAILED
/home/admin/CoverageWebApplication/build.xml:62: /home/admin/CoverageWebApplication/webcontent/WEB-INF/lib does not exist.

Total time: 0 seconds