firefox: Update version from 52.0.1 to 52.0.2

Release notes [1]:

> Version 52.0.2, first offered to Release channel users on March 28,
> 2017
>
> ### Fixed ###
>
> *   Use Nirmala UI as fallback font for additional Indic languages
>     (Bug 1342787)
> *   Fix loading tab icons on session restore (Bug 1338009)
> *   Fix a crash on startup on Linux (Bug 1345413)
> *   Fix new installs erroneously not prompting to change the default
>     browser setting (Bug 1343938)

[1] https://www.mozilla.org/en-US/firefox/52.0.2/releasenotes/

firefox.be0

@@ -2,7 +2,7 @@
 
 #export BEE_TMP_TMPDIR=/dev/shm BEE_TMP_BUILDROOT=/dev/shm/bee-root BEE_MAKEFLAGS='-j80'
 
-# BEE_VERSION firefox-52.0.1-0
+# BEE_VERSION firefox-52.0.2-0
 
 SRCURL[0]="https://ftp.mozilla.org/pub/firefox/releases/${PKGVERSION}/source/firefox-${PKGVERSION}.source.tar.xz"