dpkg-split: Do not emit epochs for unambiguous versions in deb-split header

Regression introduced in commit ce4f0311e6e7a7b5125c4e881a0f2d3a8e1eea45.

debian/changelog

@@ -11,6 +11,8 @@ dpkg (1.18.11) UNRELEASED; urgency=medium
   * Remove obsolete dpkg --print-installation-architecture option.
   * Fix dpkg error messages when parsing md5sum files to include the package
     name affected.
+  * Do not emit epochs for unambiguous versions in deb-split package header.
+    Regression introduced in dpkg 1.18.0.
   * Perl modules:
     - Obsolete Source-Version substvar in Dpkg::Substvars by emitting errors.
   * Packaging:

dpkg-split/split.c

@@ -141,7 +141,7 @@ mksplit(const char *file_src, const char *prefix, off_t maxpartsize,
 	lseek(fd_src, 0, SEEK_SET);
 
 	pkg  = deb_parse_control(file_src);
-	version = versiondescribe(&pkg->available.version, vdew_always);
+	version = versiondescribe(&pkg->available.version, vdew_nonambig);
 
 	partsize = maxpartsize - HEADERALLOWANCE;
 	last_partsize = st.st_size % partsize;