Replace usages of CharMatcher constants

Guava is discouraging these in favor of the static methods to allow
optimizations like lazy-loading of implementations.

Change-Id: I2e6ab4859ccfe5cc934f507dcbc46d2892e2dabd

gerrit-gpg/src/main/java/com/google/gerrit/gpg/GerritPublicKeyChecker.java

diff --git a/gerrit-gpg/src/main/java/com/google/gerrit/gpg/GerritPublicKeyChecker.java b/gerrit-gpg/src/main/java/com/google/gerrit/gpg/GerritPublicKeyChecker.java
index c3c886f..903bf2e 100644
--- a/gerrit-gpg/src/main/java/com/google/gerrit/gpg/GerritPublicKeyChecker.java
+++ b/gerrit-gpg/src/main/java/com/google/gerrit/gpg/GerritPublicKeyChecker.java
@@ -83,7 +83,7 @@
         Map<Long, Fingerprint> fps =
             Maps.newHashMapWithExpectedSize(strs.length);
         for (String str : strs) {
-          str = CharMatcher.WHITESPACE.removeFrom(str).toUpperCase();
+          str = CharMatcher.whitespace().removeFrom(str).toUpperCase();
           Fingerprint fp = new Fingerprint(BaseEncoding.base16().decode(str));
           fps.put(fp.getId(), fp);
         }

gerrit-gpg/src/main/java/com/google/gerrit/gpg/server/GpgKeys.java

diff --git a/gerrit-gpg/src/main/java/com/google/gerrit/gpg/server/GpgKeys.java b/gerrit-gpg/src/main/java/com/google/gerrit/gpg/server/GpgKeys.java
index a0bd4bf..49657c6 100644
--- a/gerrit-gpg/src/main/java/com/google/gerrit/gpg/server/GpgKeys.java
+++ b/gerrit-gpg/src/main/java/com/google/gerrit/gpg/server/GpgKeys.java
@@ -99,7 +99,7 @@
       throws ResourceNotFoundException, PGPException, OrmException,
       IOException {
     checkVisible(self, parent);
-    String str = CharMatcher.WHITESPACE.removeFrom(id.get()).toUpperCase();
+    String str = CharMatcher.whitespace().removeFrom(id.get()).toUpperCase();
     if ((str.length() != 8 && str.length() != 40)
         || !CharMatcher.anyOf("0123456789ABCDEF").matchesAllOf(str)) {
       throw new ResourceNotFoundException(id);
@@ -122,7 +122,7 @@
   static byte[] parseFingerprint(String str,
       Iterable<AccountExternalId> existingExtIds)
       throws ResourceNotFoundException {
-    str = CharMatcher.WHITESPACE.removeFrom(str).toUpperCase();
+    str = CharMatcher.whitespace().removeFrom(str).toUpperCase();
     if ((str.length() != 8 && str.length() != 40)
         || !CharMatcher.anyOf("0123456789ABCDEF").matchesAllOf(str)) {
       throw new ResourceNotFoundException(str);