Mark servlet-api as provided (neverlink)

After unifying JGit and Gerrit to use the same external dependency
graph, servlet-api started propagating as a runtime dependency.
This caused javax.servlet-api to be packaged into WEB-INF/lib during
Gerrit WAR assembly instead of WEB-INF/pgm-lib.

Restore the historical behavior by marking servlet-api as neverlink,
so it is available for compilation but does not contribute runtime
jars. This matches Gerrit’s servlet API handling and keeps the web
runtime classpath clean.

Change-Id: I73c310e64975f7197886a978cbddc0623e3e7590

lib/BUILD

diff --git a/lib/BUILD b/lib/BUILD
index dfe44ea..923d629 100644
--- a/lib/BUILD
+++ b/lib/BUILD
@@ -303,6 +303,7 @@
 
 java_library(
     name = "servlet-api",
+    neverlink = 1,
     visibility = [
         "//org.eclipse.jgit.http.apache:__pkg__",
         "//org.eclipse.jgit.http.server:__pkg__",